Great Eastern Trading — regarding an exchange offer and miscommitment

Address: V.I.P. Road Baguiati, Kolkata, 700054

This is to intimate that we have purchased one lg refrigerator in the month of october from great eastern trading co baguiati store. We asked there for the exchange offer with our old refrigerator. A salesman named rupam chakraborty told us that they will arrange an exchange offer with lg and a cash voucher of rs 6000 will be credited in paytm and our old refrigerator wiil be replaced by lg.
Days, weeks and month went by we did not get any response and no process of exchange had been initiated.
The person did not receive the call as usual, i once visited the store and discussed about the said issue. Now they are telling that they cannot do anything. They have sent a lot of exchange cases to lg all are done, except my case.

Need help on this.

Should i lodge an fir to the local p. S.?

Please help.