Reliance Digital — regarding water purifier service

Address:

Orion Business Park, Ghodbunder Road,Near Cine wonder Mall,thane west

We had purchased hul water purifier on[protected] from reliance digital, ghodbunder road, thane west-400604.
At the time of purchase we were told about 1year brand warranty and 2 years extended warranty from the store.
After the purchase done and invoice generated there was no mention of the said offer in the bill and we didn’t trust any verbal offers explained as they are not authentic so we told the executive about it, to which he said the invoice can not be regenerated so he did write the same on the bill and to authenticate it he had put the stamp of the store on it as he has not signed that thing and we were not accepting it..
Now when the time has come to avail the same, the store is denying and indirectly blaming us of forging the same... They are saying they didn’t give this kind of offer to the customer and it is not valid.
This is so insulting and harassment to a customer...