Agreements signed on my family's story had expired without extensions being added.?

I have sent a formal letter to the filmmakers withdrawing the agreement but they say they still have the rights to the story and will continue with the project. My concern is that they are using my story without a valid agreement. The agreement was signed in 1996 to produce a documentary film but nothing has been done since. There is no sight of a completion date. The agreement has expired on three occasions and had not been extended. When I complained that it was taking too long to make the film they agreed to add an addendum stating that If the film was not completed within nine months of signing date that I would have the right to contact other filmmakers interested in the project. But they have now said that I cannot do this as it would complicate the work they have already done even though they had agreed I could. They have said on one occasion that if I didn't cooperate with them they would continue with the project and that I would not be paid any money when the film was completed. I don't understand why they did not extend the agreement when it had expired.I have correspondence and agreements and would be thankful for some help in checking these. I'm a pensioner and unable to employ a solicitor. I also have a bad hearing problem and don't use the phone. Hope you can help. Thanks.