You are quite desperate to make your ex fall in love with you again.
It's understandable because you aware that if you fail...
the relationship is simply over.
There will be no next chapter.
You have been so depressed since the break up and the only thing that will help you right now is if you have your ex back in your life again.
You have a huge problem though - your ex is refusing point blank to talk to you, so how are you supposed to communicate with him/her as to how you feel? You have to understand that you will probably not be able to make any contact with your ex right now.
Your ex is too angry with you and is also hurting after the argument you had.
Trying to get hold of your ex now will only result in more problems.
It is too soon after the break up to try to make your ex fall in love with you again.
In any case, the more you try to call your ex and get no response, the more depressed you will become.
So the solution to this immediate problem is to leave your ex entirely alone for now.
Give your ex some time to think things over and come to terms with what has happened.
Once your ex has cooled down and his/her emotions are back to normal again, then you can try to make your ex fall in love with you again.
By this time your ex will probably be missing you and will be more willing to listen to what you have to say.
You yourself need to heal after the trauma of the break up as well, so instead of sitting around moping about your ex, do some things that will help you to feel happy again.
One great way to have a laugh as well as plenty of fun is to be with your friends.
Being with them will help you to get over the break up very quickly.
You'll have a much better chance to make your ex fall in love with you again when you are thinking and feeling more positive.
This way, when you do meet with your ex again, you will be more confident and more able to talk to him/her in a way that will show that you are sincere in your efforts, without becoming emotional.