Failure to cancel membership by Virgin Active

Virgin Active failed to cancel my membership properly early May 2023, and attempted to debit my account. They now want a couple of days to resolve their own problem, and this I am worried will result in them attempting to debit me again (making other debit orders bounce!). The call centre agent was unable to escalate immediately as she said management was away. This is not acceptable. I need this resolved today - with confirmaiton that my membership was cancelled end May as indicated originally, and that no debit order will be attempted.