Pathetic Service

I paid my account as usual on the 25th of July. Since the debit order went through I changed jobs the new employer only pays on the last day of the month so I change my debit order date after the 1st OF August to the 1st of every month now I am told I am in arrears. I explained the reason for the change in date they insist I am in arrears and then I attached bank statements then settled for a payment arrangement R625 plus R300 on the 1st oF September then R625 + R325 on the 1st if October was told arrangement is acceptable then later I am told have to pay R300 to activate the arrangement. I simply tried to do the right thing and have never defaulted on my account.