but my bill shows a charge for a phone call to an 07855 number. The call lasted 2 minutes.
Hopefully @Martin_N will provide an explanation and resolve for you but check and compare what is shown in your 'My Virgin Media'.
When you first log in, the summary page should show your phone package. Check this with what is shown in the contract page within MVM. There have been several past topics where the two do not match. My own MVM summary page incorrectly shows 'Talk More Evenings and Weekends' which should actually be 'Talk Evenings and Weekends' (which is what I am actually charged for).
There have also been some past topics with certain features disappering from packages during contract renegotiations, unbeknown to the customer, if you have done that recently.
If you have the Talk More Anytime package the 07855 code looks as if it should be included in that plan.
Did you receive and reply to the private message sent to you by @Martin_N at message #2?
The VM forum team are usually good at unravelling and resolving these kinds of issues. They should be able to help with your call charge and email problem.
Unfortunately, in regard to the price rises, the choices are to keep paying or to ring up and see if you can renegotiate in return for another 18 month contract or to move to another provider.
BT FTTP is becoming much more available now. Do you have another option via that route if speed is important to you? If speed is not that important then do have a look around at other providers. You will get new customer pricing is you are willing/able to make the move.