You are going to need to hire an attorney to straighten this out. If during the auction period the property was sold for taxes, assuming the auction was proper, you still acquired an interest in the property. The seller should have given you a deed, and you need to pursue that. As for the tax sale, the state law is that the purchaser at the tax sale has to allow redemption of the property, but they are entitled to 120% of the price paid at the tax sale for the redemption. But that is 120% of the tax sale price, not of the value of the property. Further, there may be excess sale proceeds sitting in the government's account that you could claim once you redeem the property and immediately get some of the redemption price back. As I indicated, dealing with properties at tax sales and coupled with the purchase at the auction is complicated enough that you should hire an attorney to sort through the details.
This answer is for general purposes only, and it does not create an attorney-client relationship.
You need to consult with an attorney. Make sure to let the attorney know about the auction. The situation is further complicated by the tax sale. Did you receive a deed? Do you have any written agreements?