Debit order stil going off while the contract is cancelled

I had a cell phone contract with telkom bt lost the phone n the sim but continued paying. When the contract was coming to an end they phoned to ask if i wanted an upgrade n i said no. The contract came to a end n they still debited n i was told to go cancel at the store and i did. They told me they were gonna debit for the last time that month since it was already middle of the month even though i hv nt used the data or minutes in almost a year. Im surprised to see them debiting again this month. I hv now reversed my money and stopped the debit and i wanna see if they debit againg. Im not the only one dat has this problem thats why i decided to come here and write this review