What a BACK STABB!! Seems everything up front is annd blue skies and sunshine. Then when you decide to use your time you have soooo very dearly for, either your week is not available or extra fees are administered, to use what you've already paid for.
And try and sell the timeshare. It's easier to win the LOTTO! Your 'good deal' isin't worth the paper it's written on, to anyone except the seller who charges you up front to list the *** thing.
It's a headache that will not go away, and my advice is to plan your vacations as they come rather than try and pre-plan to a limited window of use. BUYER BEWARE!!