Cleartrip — Usage of Credit Shell

Address:

Mumbai

I have to book a flight ticket from Mumbai to Bangalore - Round Trip on 13th and 16th February 2021.
When I am booking the tickets, while ticking on the "Use Credit Shell" option, I don't get an option to Enter PNR number in order to redeem my credit shell.
My Trip ID is[protected]. I have called them up at 10:15 in the morning. They said a person from the credit shell team will contact me in 4 hours maximum. I didn't receive any call. After that I have been trying to contact on them through emails, social media and their number[protected] and I am only kept on hold for 20-30 min. I have gone through the same process at least 15 times. I was promised a call back in 4-6 hours but in vain. But to no response. It is very important for me book my flight tickets asap.