Unlock my phone

I locked my phone with the AVG anti theft app,  I froze it after then.  I later change my SIM card and my device locked automatically. I've tried using the pin I locked the phone with but it did not unlock. 
 I registered a number which I can use to unlock the phone in case of necessity. Please how can I use the number to unlock my phone.  Thank you.

Hi Chinaza,

We're glad to help pointing you in the right direction. We do have a specialized team, who deals with mobile queries.
In this regard, we'd suggest you to raise a request to them via this link to sort this in a timely manner.
Note : You may need to choose 'yes' for the 1st question that is in the above link to request answer via email.
Thank you for your understanding in advance!