False theft case filed how can II defend myself

I was livin @ a hostel frm 2yrs which i left bfore 6-7 mnths..many thefts occured betn that period n after i left hostel.last month 1 of my frnd came to live ther with whom i had money issues n other persnls so i did theft his phone as revenge bt just his nt of ny othr roommate of his. When he knew tat the owner now want to file case against me suggestin i did all thefts at tat hostel even though i did not.. What can i do?