Debited on unknown account by Cell C

Good day I am writing on behalf of an elderly gentleman. He is 84yrs old. To his knowledge he had 2 Cell C contracts. For himself & His late wife. He just found out he has a 3rd account he does not know about. According to him he has been debited since 2019. He has phoned & drove from Margate to Galleria Mall in Manzimtoti to get assistance but failed. Can someone please help this elderly man.