Shoppersstop.com — trouser not fitting well - defective

Purchased park avenue trouser from shoppers stop malad west store (Inorbit mall) after reaching home realised that fitting is not proper while walking it’s not comfortable, now store is denying to accept as its been 2 months
I have original bill and tags of product are also intact. Need to get product replaced as it’s faulty piece. Even after purchasing from expensive stores the quality is poor