My account was debited early, outside of the contract agreement

My account was debited early, outside of the contract agreement. I had earlier opted out of an sms they had sent in Nov asking to debit early. Despite me opting out, they still went ahead to debit my account before my pay date. This left me stranded and my attempt to phone their call center asking for a reversal, I'm told that the reversal will take long and I would have received my salary by then. I asked for an immediate payment be made because our bank facilities have that option and my call got dropped and I was unable to make a connection again because they were now closed.