Makro RCS credit card with interest rates from hell!!!! !!!!!

I opened a makro rcs card, then the horror started 3 months down the line the app stared giving me problems end of June I couldn't login the app to make payment like I usually would, I deleted and reinstalled the app did all kinds of stuff I did numerous times to have other alternative payment methods and the call centre kept telling me to do what I already done I told them I don't have time to go to a store can they provide me with an eft option the consultant advised they don't have that option I eventually called again and managed to make payment of R500 as on the app my last amount payable reflected as 400 and some odd rands so I paid more!

4th July I receive an sms that my acc is in arrears I should pay r110. 83 weird right cos I paid more than what was needed so how? at this point I didn't have money. 2nd sms 5th July R120.83c outstanding! 8th July R194. 20 outstanding, 14 July I'm now on R390. 03 outstanding? Someone explain how the ****??????????? I need to cancel this ****ing card cos no ****ing way am I going to be ********** like this!