GIVEN SOMEONE ELSE'S TELEPHONE NUMBER ON NEW CONTRACT

I took out a new contract and is now receiving threats on SM and calls from the previous owner of the account who is not payment her debt with companies! the person is actively giving out the number left right and center to everyone and even app**** for a agent position with Homechoice as far back as a week ago! when i called to Vodacom customer care to report this i was told to deal with Legal and Legal say customer care???

who will fix this or give me a NEW number as i will be dealing with other peoples problems. this was a NEW contract - WHY was i given someone else's problems and telephone number????