Quick to process debit order, slow to refund

I joined Virgin Active in the beginning of January 2015 via Momentum Multiply. I was advised that they were running a promotion whereby my 16 year old son did not have to pay for the first 12 months. All the paper work was completed and we became members. A week later my son's application had to be re-done and I signed a debit order to commence 01/02/2015 thinking this was for next year. On realising my mistake I wanted the contract amended, both the sales consultant and the manager said that they could not amend the contract, but assured me that head office are aware of the promotion and the debit order would not be processed. The debit order was processed on 31/01/2015, sneaky way to take your money. I called to complain and was advised by the acting manager that \head office were definitely aware"of the promotion and should not have processed the debit order until 01/01/2016. Still waiting for a call to say refund is being processed."""