Foreclosure on seller finance second lien

[Mike]

I bought a property for $135,000 and then sold it for $179,000 with 12% seller financing. The buyer is in bankruptcy chapter 13 now (4 years after the sale) but they have not listed the secondary lien (seller finance) in the BK. I don’t want the 1st lender to foreclose on the property. But how do I go about satisfying the 1st lien and then foreclose on the second thereby regaining the title. The current property value is round $210,000.