Commit *****?? Yet threaten legal action

Both my parents (in their mid seventies) have had an almost identical experience with two contracts taken out a week apart. My mother took out a two year contract and paid for it in advance. Strangely enough now that a year has passed she has been locked out and told she needs to pay a monthly fee. An addendum has been produced that does not bearing her \signature". However it isn't her signature. She has called and been given two references but no response. Isn't this breach of contract and *****? What to do?<br> <br> My father did the same two weeks later but when filling in the forms there were no \""prepaid\"" forms available. so they used the regular form. The sales person asked for banking details even though it was paid in advance. He claimed they will debit an admin fee as a once off on the first anniversary. As it happens he has now been debited monthly as the second year has \""started\"". <br> Upon investigation the admin manager claims that there is no such thing as a two year prepaid contract. Even if that is true on what basis can they debit monthly if he has not signed permission for a monthly debit and a corresponding amount. What is most alarming is the lack of response."""