being ****** by telkom

A telkom sales consultant called me when i was due for a contract renewal, i agreed to a device upgrade, however the device delivered was not the correct one, i called telkom and notified them, they sent a courier to come collect the device promising to replace it with the correct one and since iv been calling telkom for the past 8 months and still not solution, i am being sent pillar to post and the telkom stores refuse to assist me because i agreed to the contract telephony, each time i call the telkom sale i am being promised to be contacted within 48hours and no one ever calls yet my bank account is being debited each month for something i dont have with me .