Any company who asks for fees upfront has no interest in selling your timeshare because they have money from you, and that was always their intention--to steal from you.
Do not sign up with anyone who cold-calls you at this point. After you inquire with a company like this, you will be put on a list of scammers who have all sorts of ways to take your money.
If you have a timeshare worth real money, you can sell it. If your timeshare is at a legacy resort, you might not even get $1.00 for it. But you can attempt to give it away here on TUG under the Bargain Deals section of this BBS.
Good luck.