Debit after cancellation

Following the cancellation of my gym membership, and an assurance that there will be no further deductions following the last one on 1 February 2018, there is still a deduction on my account that went off on 1 March 2018. I emailed virgin active enquiring about this, I also sent a follow up email. I need the matter resolved , the debit cancelled and my money reimbursed as per the cancellation agreement but I am yet to hear from them