Im not happy at all! Please help

I bought a pair of shoes last year via Superbalist and in January for my last payment, my bank card was renewed and haven’t been able to update my card on the pay just now website at all. I sent countless messages an all I get is a bot response with no help! My fees keep on climbing and I am not paying anything other than the amount I owe them of R499.00. The fees keep on going up and there is no help, I’ve kept funds available on my card, and what frustrates me the most is not being able to change or add another payment method.