To uninstall avast run http://www.avast.com/uninstall-utility (You will be prompted to reboot into safe mode click “yes”)
To re-install the proper version
http://files.avast.com/iavs5x/avast_free_antivirus_setup.exe
http://files.avast.com/iavs5x/avast_pro_antivirus_setup.exe
http://files.avast.com/iavs5x/avast_internet_security_setup.exe
http://files.avast.com/iavs5x/avast_premier_antivirus_setup.exe
The person in charge of third party support may be contacted via email nekvapil(at)avast(dot)com
Place a link to this thread and relate to him in detail you complaint(s). I’m sure he will want to get you issue resolved. 
In the future feel free to seek assistance here on the forums. Our help is absolutely “free”. 