PLEASE HELP UNBLOCK MY PHONE

I AM VERY UPSET, I would like to Request The Unblocking of my i Phone 6's with IMEI: *** AS I RECEIVED A MSG ON MY NUMBER *** SUGGESTING THAT MY TC REF NO: ***4 HAS BEEN ESCALATED WITH REFERENCE NUMBER ***, I IMMEDIATELY CALLED MTN CALLCENTRE 135 ADVISING ON THE SITUATION AND THEY SAID THAT A PERSON BY THE NAME OF BONGANI REPORTED MY FONE AS ****** AND I DISPUTED THAT AND EVEN ADVISED THAT I AM CALLING FROM THE PHONE IN QUESTION AND MY NUMBER AS WELL AND SUGGESTED THAT THE NUMBER IS ON THE WATCHLIST, HOWEVER THE LADY ASKED ME TO HOLD AFTER THE LONG HOLD SHE THEN ADVISE THAT THEY ARE UNABLE TO HELP ME AS THE SO CALLED BONGANI IS INSISTING THAT THE PHONE IS HIS, I FURTHER SUGGESTED THAT WHY DONT THEY ASK HIM THE SECURITY QUESTION ON WATCHLIST AND THEY SAID I MUST SEND PROOF OF PURCHASE AND THE FONE BOX TO: *** and I did at 1245 today 15/10/2019 HOWEVER AT 1530 MY FONE WAS BLOCKED AND I JUST CALLED MTN AND THEY SUGGEST I EMAIL THE SAME DOCUMENTS TO : *** AND I DID NOW IVE BEEN ADVISED THAT THE PROCESS WILL TAKE UP TO 72HOURS AND I AM STUCK AND THIS IS NOT THE FIRST TIME THIS IS HAPPENING, WAT MUST I DO NOW PLEASE ASSIST.