If you are on any of VM's TalkAnywhere Plans then calls to 01x, 02x, 03x, 077/078/079 (mobiles), 08x and international calls are included within the plan and therefore not subject to any connection charge.
These call plans, however, are
NOT unlimited as they all have specific limit of maximum number of minutes per month and range from 200 mins (costing £20) to 800 mins (costing £40).
If you are on VM's TalkWeekends (Size: M), Talk Evenings & Weekends (Size: L) or TalkUnlimited (Size: XL) then these plans only include calls to 01, 02 and 03. Calls to other number ranges like 07x and 08x are excluded at all times and attract their own charge as well as the connection charge.
If you make calls to numbers outside your inclusive allowance or have gone over any inclusive limit (where applicable) then calls are chargable and will attract the huge connection fee.
VM call charges for calls to 0845 and 0870 are the highest out of all the other landline providers as is their connection charge (from November).
I suggest you clarify what is the name of the price plan you are on and then refer to the above. Ignore if they say calls are included or the connection fee does/doesn't apply because the information they tell you is sometimes wrong (and this wrong information increases when you are through to someone not from the UK).
More information on VM's price plans can be found
here but for the record VM's TalkUnlimited is only unlimited for calls to 01, 02 and 03 numbers and therefore all other calls are excluded and attract the connection fee charge.