Trying to Restore my backup of Avast Passwords

Yesterday after upgrading my iOS, the app asked password asked me for a master password, and I didn’t know it after communicating with your support team. They have told me to try and reset the password on the website and then again uninstall uninstall the software now I am in a position that I have the software on my iPhone, but I cannot enter as my backup is not there and I don’t have another device authorizing Now. I have the email that you A few years ago when I became your paying customer for Avast password, I’m trying to restore and I’m getting an error. Please help I’m stuck and lost.

Really need someone’s help please

I don’t have another sync device. I have one PC with Windows 10 But I don’t get any request to authorize the iOS device there.