Well the previous owners are flat out wrong about their not being any problems, not to mention owning an intact dog has its own drawbacks as far as marking, possible male aggression, accidental breedings, which would only furhter his crytorchid problem. The retained testicle is at a MUCH higher risk of cancer due to the body heat by being retained. Not only that but buying a dog comes with it's costs, such as neutering. That is a standard pet cost and not something that has to be covered by the breeder. Not to mention you got your puppy for a song, if the breeders did the appropriate health testing, which costs a lot of money. If they didn't then you paid too much and bought a BYB puppy and should neuter him regardless, even if he had both testicles, as his breeding line hasn't been checked for inherited diseases. It is in HIS best interest to neuter him and you weren't sold a "faulty" dog. Dogs aren't perfect and people aren't perfect but you should be careful of the source you buy from. Since cryptorchidism is an inherited trait, he should never be bred anyway, even if he was from champion lines with all of the health testing in place. He should be neutered and it is for yours and his best interests.