Unauthorised transaction#394070

On 28th October 2018 at 7:28pm I got some messages that RS 50,rs50,rs7889 was debited from my account through debit card without my authorisation. Immediately I blocked my card and i reported a complaint in bank. The complaint was registered but I didn't get any positive response from them. What should I do to get the refund of my money.248742000103177 is the POS of this transaction.please help me.