My child does not listen to me!

Now that Sonia is more expressive in her needs and wants, it is ironic in a sense that I am happy about her development, but at the same time very frustrated when she doesn't follow what I want her to.
I find myself constantly yelling at her when she doesn't obey my orders to pick up her toys, or to finish that cup of milk. Then after yelling I would be all guilty and angry at myself for demonstrating such a bad behaviour influence on her.
There was once I was bathing and I asked her to clear her toys which were scattered all over the room as we were preparing to go to bed.
"Sonia can you please keep your toys? After mummy bathed we will read some bedtime stories, okay?"

She would nod or seemingly agree. And then she will ignore my requests and continue with her tinkling. And within my 5 minute bath I constantly check out (I leave my door open a little when I bath) to see whether she did clear her toys.

And she DID NOT.

Not even a single toy.

I reminded her again. Check. Reminded. Check. Reminded.

Until I got to the warning stage.
"Please keep your toys, when I finish my bath I want to see you finished keeping your toys."

Of course she didn't heed my advice. And suddenly some words from an article I've read hit me hard. This is why parents are often caught repeating and repeating their words and the child ignored until the parent shouted. Children will only listen to you when THEY KNOW YOU'RE SERIOUS.
Because they know you will repeat yourself and unless until you mean it, they are not going to listen.

And of course I do not want Sonia to get used to my repeating orders. So I stopped myself from repeating-ly asking her to clear up her toys, shut up and continued my bath.
When I came out from the bathroom, did my skincare routine, I sat down and asked her for the one last time.

"Are you going to keep your toys? Its bedtime. If you do not want to clear your toys I'm going to put them outside."

No response from her.

So I got up, put the toys that were scattered on the floor into a recycle bag (because I am staying in my aunt's house and do not want their clearing to be scattered with toys), and placed them outside of our room then shut the door. I meant to leave them there overnight.

The moment the door was shut she cried so loudly that it was clear that she was shocked. Never she thought I would have meant what I said. I did not comfort her but instead I told her that I have told her the toys would be outside unless she cared for them and put them back after she has done playing.

Whilst crying she pleaded for me to open the door. As heartache as I was, I am serious in letting her learn her lesson. I asked her whether she wants her toys back and she nodded.

"Are you going to keep them? Put them back in their place?"

"Yes"

With that answer I opened the door and got her toys back in. She stopped crying and started to look into the recycle bag. The funny thing was that she placed the recycle bag and everything inside beside her toy rack and assumed that she had done her job. Withholding a laugh I had to pour everything out from the bag and then only she started putting everything back to their place.

I do not know whether what I've done was considered harsh or cruel, I support positive parenting, but sometimes I felt that they need to learn the hard way that I really meant what I said.
Maybe I repeat my words many times and she was conditioned to ignore me, but now she will relearn how things should be.

There are several things I need to remind myself, and as a reminder to other caregivers too:

1) Say things and do them immediately. 
   Eg, It was often that I said 'let's brush your teeth, or take your bath', and then sat down scrolling on  
   my ig feed for a few minutes, leaving her to tend to herself before actually taking the move to the
   bathroom.

2) Practice behaviour that you want your child to practice. 
   Eg, I have a bad habit of putting stuff here and there and forgot where did I placed them because I
   did not put them back where I took them. I realized that Sonia is doing this too. She would find
   some small toy that belonged to her cooking set and put them into a bag that is nearest to her at that
   moment. I saw what she did and reflected back to my own behaviour, which clearly needs to
   change. It wouldn't be easy to change a habit but I would work on it.

3) Say things once and mean what you said.
   Eg, similar to the above experience, I will only say things once, and she will be aware of the consequences if she ignored the first message. Of course the consequences need not be scary (such as "I will slap you" or "the monster will get you"), or unrealistic (such as "I will throw away all your toys", at least I wouldn't throw away my money), or bribing (such as "if you keep your toys I will buy you chocolate tomorrow", this will only create unnecessary rewards when they are suppose to do what they are supposed to do).

Most importantly, I do not shame my child (such as "you're useless/hopeless/naughty") or say things that hurt their feelings and made them lose trust in you (such as "I don't love you anymore" or "If you don't keep your toys I don't love you anymore).

I believe that children are developing humans and little things that we do served as experience and building blocks for them to become the people of tomorrow.

Comments or your experiences in dealing with these situations are welcomed!!