Charged R 202.70 for their “OWN ERROR”

I had contract with Telkom mobile for LTE, regret day I signed up. Cancelled my contract last installment was suppose to be R99. 49 but Telkom debited my account R 199, lodged complain with no response until I reverse the debit order, then Telkom responded and request I pay R 99.49 which I did pay, now they invoice me for R 202.70 “Payment Rejection Fee”. Won’t advice anyone to do business with such bullies,