Hi

You need to write to the debt collectors and given them the proof of this payment you made (they have been instructed by Vodafone so should then liaise with them) and then copy in Vodafone head office. You could not have made £330 worth of calls if the phone was cut off. If they cut the phone off it would help if you had the date that this happened as the further calls made will be registered and dated so you can prove then that it was not you making these calls.

If the house is your mothers and the items in it are your mothers, then they cannot take anything as the debt issue is not your mothers, it is yours. The debt is linked to an individual, not a property.

Goodluck.

Bailiffs do not have the right to force entry into a property but if somebody lets them in they do have the right to return at a later date to take goods. Property belonging to someone else cannot be seized to pay off a debt you owe. However a debt collector or bailiff will not know that you do not own any property at your home address, until you tell them. It is highly unlikely that Cap Quest will send a bailiff round for such a small debt so do not let the threats from Cap Quest scare you too much, but do make sure that if a bailiff was to visit that no-one lets them in.
Debt collectors are unable to pursue a debt if it is being disputed. You need to ask Vodafone to formally investigate the bill outstanding. Make sure you know all the dates of what happened and when it happened, so that they have the full picture. Ask them to confirm they will put the debt collectors on hold whilst this is investigated and keep a note of the name of the Vodafone employee you have spoken to.
If you are unsuccessful in having the debt cancelled, the collections department at Vodafone should be able to set up a payment plan, where you repay a set amount of the debt each month. As long as you stick to the terms of the payment plan you should not have any debt collectors call round.