VM's billing systems were all inherited from the predecessor cable companies that NTL and Telewest bought up. They do not operate in real time and the best VM can do with them is to update payments only when a new bill is generated. That doesn't mean you are stuck. If you pay by direct debit or through a bank account (debit or credit card) you can always check with the bank/card company that payment has gone through. But if you pay by cash you are out of luck.
Superuser 2017/18 Use Kudos to say thanks Mark answer as "helpful" only when the problem is solved Please don't send me private messages unless I ask you to. I do not work for VM. The advice I give is based on my best understanding of VM policy and practice. You rely on it at your own risk.