Phone locked out with Avast mobile

I tried to install Avast mobile software about a year ago when I first bought my mobile phone and had so much trouble with it I thought I had deleted it from my phone and deleted device off account. I have now unlocked my phone from my current contact phone company y ok and inserted their new sim card. My phone is now locked and I have a message This Phone Is Lost or Stolen
I tried putting the old sim card back but that does not work. I found the pin number from when I first added the software and that does not work.

Any suggestions as to how I can get my phone working again

HELP

Surely someone on the forum can help with this problem or do I just buy a new phone. Tried factory reset and that does not work. My home lanline keeps ringing with voice texts, I assume I must have given thisa number when I first installed Avast mobile, antitheft.

How do |I get a pin to unlock and use my phone again.

I have the same problem, last Saturday the siren on the phone started to go off and said that my phone was lost or stolen, which of course it wasn’t. I tried entering the pin but it didn’t work, so I requested a new one which was sent to my nominated number. 3 times I requested it and all three new pin numbers didn’t work. I took my phone to the phone shop and they said they would have to sent off to be reset but couldn’t guarantee it would be fixed and I would need to purchase another phone. I submitted a ticket on Sunday and I am still waiting for a reply and my phone still isn’t working. Can someone please help me with this situation as this is a new phone which cost me a lot of money.

Which manufacturer and model are your smartphone? Is it rooted?