State Bank Of India [SBI] — Reversal of Debit of Rs. 770/-., wrongly debited through POS machine

I was used my ATM card on 17.12.2016 for purchasing a woolen jacket in Durgapur through POS machine. After swipe ATM card in POS machine, POS generated slip shows that " TIMED OUT TRACSACTION . CONTRACT YOUR CARD ISSUER FOR REVERSAL OF DEBIT" . I found that Rs.770/- debited in my saving account but the same was not credited to merchant establishment.
In this connection, copy of POS machine generated slip is also attach for your ready reference. I also lodge complain online Ticket No. PO[protected]. and another complain through my bank Ticket No. Ticket Number: PO[protected]. But no fruitful result yet to be received. Till date I am not received 770/- to my saving account.

Saving Account No.[protected]
Sate Bank of India
Branch: CHITTARANJAN
State:-WEST BENGAL
Branch Code :000241