I'm so sick of mtn

I do not know how many times I have asked mtn to change my debit order date. I added a new contract to what I already have and asked them to change the debit order date. I waited for the Debit order to go through. Nothing happened. Waited for the old debit order date and still nothing. Mtn is in breach of contract and I will soon be contacting my lawyers if this is not resolved to my satisfaction.