Not refunding amounts incorrectly deducted

I cancelled my contract with Planet Fitness (Soneike Branch) in October 2014. However in November and December they still deducted the monthly membership fee from my bank account. I called to find out why this was done, and they said that they would refund the amounts. I had to send them the detail of the amounts + my banking details. Which I did twice in December. Every time I call to follow up, I am told that the query is with the finance department and that they will phone me back - which never happens. I would like to know what is foing on?