IDFC Bank — Fastag

I have been trying to recharge my fastag for a couple of months now, but initially, any tool I tried, Paytm, IDFC's site, they kept telling me that I do not have a fastag registered with my phone number.
I have spent many hours trying to reach to customer care on phone, and most of the times, after waiting for over 10 minutes, my call is disconnected. I finally got to speak to a customer care rep last week, after trying for weeks. I was informed that my fasttag has been blocked and I will need to go to the Website and upload a copy of my RC. I have been trying to do it for the past one week, but the system just will not accept the image. I have tried different formats. The limit of 50 KB for uploading an image is so low that I had to try multiple tools to reduce the filesize, and finally when I was able to get it under 50 KB, the system throws an error saying the format is invalid. It is a JPG file, and the filesize is well below 50 KB.