Mobile Home Park - Selling Lots

[Family of 3]

I have a question, that I need some help with, we currently live in a mobile home park and rent our lot, we have been here for about 6 year, and have been trying to sell our home for about 3 years, our Mobile home Park owner, just sent out a certified letter stating that if we sell our homes we must also sell our the lot we currently rent which means we must know tack on an additional $36,000 dollars to the price of our home. The lots are about 130 x 40, we dont feel this is a fair price for the lot, another resident had an appraisal done, and it only came in at $17,000 - what can we do????