First of all if you think your timeshare has any resale value you need to put that misconception aside now. If by chance you would have a high demand week at a high demand resort you might get lucky and get maybe $1,000 or even as much as $2000 for it. But it is more likely that you might get $100-$200 or even have to give it away and pay some or even all the closing costs too. And here is the worst part, you would have to pay it off to be able to sell it. Unless of course you manage to find a sucker dumb enough to take it over along with the balance owed which is something none of us would recommend even trying. I know this must sound a little harsh but it is the reality. The timeshare relief companies you see on TV, get calls or letters from prey on people in your situation so please don't give them a penny because that will just be more money you lose.
If it is a financial burden you can't afford your only option may be to let the resort foreclose and take the hit on your credit.
Many of us discovered that what be bought had little to no resale value despite how much we paid. We kept what we bought and have had many years of wonderful vacations. When we bought more we bought resale for pennies on the dollar.