@Gillzlaing83 Welcome to the community and thanks for posting, I'm sorry you've received an unexpectedly high bill. If you're on the monthly payment plan it may have automatically recalculated if a debt has built up on the account over time if the £55 had not been covering the full amount of your bills or you may be correct in that you've been charged for the Hub but this should have been advised at the time and will be itemised on your latest bill.
The quickest way to get an answer would be to contact the billing chat team on this link. Post back to let us know how you get on.
