Poor customer service.

The service, or lack thereof, received from Winchester Gym company is really appalling. I have been calling continuously for days on end to have my banking details changed, there would be no response at the Admin department, nor at Accounts. Eventually got through to a Nelly, who was initially supposed to send me a change of banking details form, which she didn't. She eventually sent the form after I got through to her, because I had to follow up. I specifically asked her to please have the banking details changed as well as the debit order date. None of which has been done, the last email from Nelly Mavimbela was on the 24th February. Whenever I call to speak to her, she is gone to checkers according to the lady at switchboard/reception and I never get a call back. Can someone other than Nelly Mavimbela please assist me, as its clear that Nelly doesnt pride herself in customer service.