Change of bank details

Hi. I have been asking to change the bank details as the debit didn’t go through successfully which I am being told that I have to wait for 3 returning debit orders. Who must pay for the returning debit order fees. I got an email stating that I can pay through payfast but there is no link. Your agents take they ample time to respond back to clients. You are not treating clients fairly that we have to wait for the services to be disconnected in order to create a new voucher. Please find ways in order that clients can change their bank details in time rather being told to wait. I am really unhappy this.