Cell Phone Payment going to a random account!!!

I have paid my cell phone bill four times in the past 15 days, and it was still shut off.  Two of the payments were made from my cell phone and they went to another user's account.  He has never lived at my address, nor do I know him.  I would like my account credited.  I have had the same cell phone number for over 5 years.  I have spoken to multiple useless agents who were no help.  I have proof of the payments but they say they cannot see them.  Not sure how someone else can use my address and phone number and get away with paying nothing.  I have an Xfinity internet account and cell phone.  My payments went to neither of those bills.