Cellphone contract

So very unhappy with telkom service i took a cellphone on contract and am Suppose to pay R330 including insurance and ever since i took out this contract it's been nothing but a pain in the ass every month i end up paying more than am suppose to pay...They always tell me the debit order bounced fine I pay the ridiculous invoice fee of R240 something they charged last month i payed 844 i called asked to changed the debit date to the 5th of each month believe it or not telkom yet again the want me to pay 542 for what? I hate and regret the day i took out a cellphone contract with this services provider this is day light ******* being charged for February invoice that i payed for.. I. Wish they could take their phone i would never ever recommend them to anyone