Title Issue on Tax Foreclosure Discovered During Refinance

[Scott Bremer]

Hi all. I purchased a house at a County Tax Foreclosure auction in 2019, fixed it out, now a rental. Attempting to refinance, the title search company found an issue: they don't feel that the County I purchased the property from adequately informed the previous owners, who had abandoned the house, what was going on. They say I can either do a a) Quiet title action or b) Get the prior owner to sign on the line that is dotted. I'm worried that they'll sue to get the house back. 

Does anyone have any experience with this or suggestions for a way forward?