MWEB taking money for NO SERVICE

Mweb has been deducting a monthly premium for my account for years. I have not used their services in about 10 years but they still take over R200 per month. That is over R20 000. I have tried repeatedly to cancel this but they just won't cancel the account because I don't have my log in details anymore - remember I haven't used it for 10 years. They continue to take the money, not deliver any service and refuse to cooperate with me. I have since moved to Australia and so it is now impossible to get any help from them.