Byjus - Not refunding full amount after cancellation

We had purchased a product for our kids studying in class * and their sales person used completely unfair means to buy the product even though we were not ready to buy the product. When that person said if we cancel product within **days they will refund full amount without any charges. So we placed the order and later realized after talking to a few parents and seeing reviews. We cancelled the order on the same day (**th March ****) as we purchased. After many follow-ups, they returned partial amount and refused to return remaining on last Friday and said do whatever you want we will not return the remaining amount. Later in that evening I again sent email to refund the remaining amount. We received a call from them that they will talk to the bank and find out what can be done and if required will refund remaining. That time they acknowledged their mistake during the conversation but they are not initiating the refund process. We are after them and have sent multiple emails since Monday but they are not responding once again. Please request you guys to help us.