Head office's incompetence

As per my contract with the gym I have ask for the debit orders to be run on the 15th of every month and for some reason the gym has not run a debit order since the 15th of May, and this morning I receive a message stating that if I do not pay my account I will be handed over for collection. I have phoned customer care to query this and when I asked why they did not run a debit order, they said the accounts did not run debit order so they will run a double debit next month (15 June) to which I refuse they do. now when I came to the gym to train I was refused entry reason being I have payments issues. I spoke to the branch manager and he checked my account and said that I have nothing outstanding to pay. I have been with this gym for over 3 months and every month is the same story.