Complaint regarding Snapmint EMI problems

I used snapmint a month ago to buy products worth 2000rs from Amazon . So for 2000rs the emis were made by them for 2 months that is September and October and the last dates were 3rd of both months. So as the last date for September EMI was coming, I paid the first EMI of 1000rs to snapmint via gpay. The amount was debited from my account and gpay showed transaction successful. But on the snapmint app it conveniently showed payment not completed. I thought it must be an error and it would take 24-48hrs to reflect the payment on their app but it didn’t happen and they are still sending me msgs that I haven’t paid the EMI and I will face penalties and my cibil score will be affected. I’m trying to contact them via email , call and their social media handles but I’m failing to do so as neither anyone is picking up the calls/answering the emails nor they are contacting me any way. They are just sending me msgs so that I pay the same amount once again. What if I pay it again and they do the same thing, then it would be a scam once again. I just want them to contact me and resolve the issue because I’ll not be paying the same amount again and I don’t want my cibil score to get affected because of them