There is a avast version for mac's and it is free.
Your have two problems.
First one is that you have submitted multiple tickets.
avast is using a FiFo system and each time you submit a new ticket (or change the current one), you will be put back to the bottom of the stack.
Second one is that you have no patience.
avast is handling tickets within 1-5 business days (time depends on how busy it is, if there is a holiday etc)
There are no multiple phone numbers for support with avast.
There is only one and that is for help with avast and PC's, not mac's.
You can cancel the subscription yourself.
https://www.avast.com/faq.php?article=AVKB24