Sun International Vacation club timeshare

I purchased a sun international vacation club timeshare for R21 600 in December of 2017.I haven't made use of the timeshare since its purchase. Recently, I made an enquiry with Sun International about selling it and they refused the opportunity for me to sell it privately and informed me that they had first right of refusal, and only they could buy it back from me the owner. I received an offer of R9 223 for a balance of 8 years left of a 10 year timeshare. This offer indicates that Sun International does not value their timeshare and I think that buying these 10 year timeshare memberships from Sun International is just a *******.