Real Estate / Property ownership in Poland - purchased solely in my name using a Polish mortgage; my ex's parents live there [5]

Hi there, Ive just found this forum, and Im hoping someone can offer me some advice. I am from UK and I purchased a property in Poland in 2007 using a Polish mortgage solely in my name. My then partners parents moved in, and were paying the mortgage payments directly to the bank, instead of paying me rent. I then split with my partner, but agreed to let her parents stay there. My partner got me to sign some paperwork which gave her permission to pay the utility bills on my behalf, which was witnessed and counter signed by a solicitor. I have not had contact with her since then, but obviously still have a mortgage and property deeds in my name (but dont have any paperwork for deeds- her parents are holding them, and all I have regarding the mortgage is the agreement number and the bank name). So I am wondering now, where do I stand? I am looking to buy my first property in this country, but dont have any capital- how would I start going about using the Polish property for equity? Would appreciate any ideas. many thanks