UTTERLY DISGUSTED

I called in to change my banking details and was told theg can't do it but its customer care they sent me a link to pay the payment but the link does not work and the payment does not go through but it keeps saying it was successful. I called over 20 times and nobody can assist me. I have been without internet for 3 days they said support will contact me but I have not received any communication from them.I am so disgusted and requested to rather cancel. I want nothing to do with them anymore