You owe them the dues. They don't owe you a darned thing, and, in fact, never have to even come through with anything (though it would be bad business practice to do that). Furthermore, many people find out later that they were not eligible for the referral either because of the state they live in or because the referred party had had some contact with
DVC before that had been documented (this happens a lot). They are still giving the F&F discount in the latter case, but I don't think they are bending on their normal referral rules otherwise. Remember: A beggar can't be choosy. If you get something, it's a bonus. If you don't, you have exactly what you started with (unless the referrer did something shady in terms of "selling" their referral as some people have offered to do in the recent past).