I found a timeshare sale/rental site and tried to rent a timeshare at Oyster Bay Beach resort. The person handling the rental was affiliated with or worked with GTA Holidays. Has anyone ever heard of this or know anything about it? The gentleman said we could get a unit and promised to get back to me with voucher numbers but never has. Just wondering if it is some sort of scam. He said his firm was some sort of travel wholesaler.

the site I found this on was vacationtimesharerentals.com

Have not used this company, but have used a similar company affiliated with skyauction.com
You use your voucher to cash in on a timeshare.
Just stayed at Simpson Bay Resort for a week in a one bedroom for $419.00 which was a $100 upgrade than a studio.
Can recommend skyauction, but make sure want you want is available first. Usually offer mostly off season and last minute. Since we travel in August, we had good luck.

This would be enough to make me look elsewhere.

I recommend Endless Vacation Rentals an affiliate of RCI and part of Wyndham World Wide for timeshare rentals and if you belong to AARP a 25% discount is available on many rentals.
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Endless VacationRentals

We have used them over the years for rentals on Sint Maarten, Aruba and Florida.

I certainly hope the OP didn't lose any up front money. That would be terrible.

When were you trying to go to OBBR? Booking there, January to April, is almost impossible unless you own a unit or know someone who has already reserved a unit and can't use it.