Skylight Solatube Diffuser Cracked

Hi, We just purchased a home with a Solatube 10 inch skylight where the diffuser is cracked. The home was built in 1995. When I called the manufacturer they said they don't make that model anymore and said you have to buy the whole bottom, diffuser, and lens affect. Do you know of a cheaper way to fix without buying the whole unit. Places where older skylight parts are sold, generic diffusers that would work, any advice?