I recently purchased Airtel 4G LTE. It never worked on my Windows 7 laptop with latest Windows patches. I had to re-image Windows to get the device working. The device worked for 3 days and as soon as I applied all the latest Windows 7 patches and hot-fixes, it stopped working. It never worked after that. I got the standard response of "Re-install the software." I contacted the technical support. But it did not solve my problem. Later they sent a technician to my house.
He just uninstalled and re-installed software which was of no use. The software was giving an error indicating that "no Sim card" even if there was a valid/working SIM card. They promised me a remote debugging session, that never happened.
Finally, I had to go for a disconnection, but they charged me the rental for all the days even if device was not in working condition. I really felt terrible after purchasing the dongle from Airtel.
I have decided not to buy any product from Airtel from now on.