My Flat in possession of sibling

Hi, I hv bought a flat in 2007 in single owner name, my name in Ahmedabad. Now, I hv shifted to Surat. since dad gave some 50% of initial down payment of total 2-lakhs out of total 11 lakh flat value at that time. Balance 10 lakh was funded by my bank loan n repaid by me. Effectively flat costs 15 Laks including bank EMI total after 5 yrs. however, there are other bank transactions wherein I have given amounts more than what i received from him, to invest in stocks in dad's name, FD, other use etc. Dad has a pention income living with brother in my apartment and he is wasting money in stock market nowadays? Brother dont want to leave flat? i m fed up from such encroachment on my property? Now, Dad n Brother lives there and I asked many times , but they dont want to leave the property. How can I get possession of the property or sell or any other option? what can i do?