how can i get a clear title

I bought 1.75 acres in Flomaton Al. for 2500 5 years age. When I went to the tax office to put it my name they told me I only owned 10/11ths of the property. The property was purchased in a tax sale by another party from which I purchased the property from. The other 1/11th of the property is ownwed by the Pleasant Foundation. I asked them if they would sell me the 1/11th they said no . I asked them if they wanted to purchase my share of the property they said no. Then I offered to donate it to the Pleasant Foundation and they would not give me the legal information which leads me to belive it is a bogus tax shelter ... Is ther any legal recourse I can take. I wanted to donate it to them so I could write it off on my taxes..