Gym Company Worst service ever - Account

I cancelled my contract with the Brackenhurst branch in September 2024, my last pyment being December 2024. In January they deducted another payment, i reversed the debit order and advised my bank to stop the debit order, NOW i keep getting text messages saying i am Overdue in my payments. I have contacted this branch advising them but since keep receiving text messages saying they will hand me over!!!😡 useless bunch!