Vodacom refusing to cancel cellphone contract.

My wife has been trying to cancel her contract with Vodacom for more than 2 months. She went to the store at the end of November 2020, and they gave a number, ***, that she must contact to do the cancelation. She phoned the number 3 times during the 2 months, and the contract is still not cancelled. Every agent she spoke to promised that she will receive a sms stating proof that the contract will be cancelled, but till this day no sms was received. The debit order goes through every 25th from her account. Very dissapointed in an international company.