You'll get the cashback, but one downside I faced in chortel is basically, as soon as your pack expires, you stop receiving incoming SMS & calls. Personally this was a deal breaker to me. I ported from Jio to chortel, experienced this bs and then ported back to Jio, because ironically 1 day my pack expired and for the recharge to go through using the axshit chortel cc I would have needed an OTP, which I wasn't receiving as the pack expired, so missed on the cash back, had to process the recharge through UPI; Plus with chortel you can't call a lot of bank's customer care numbers. You would need to recharge with separate voice and talk-time kinda packs like in the old days. Personally I have 2 numbers, and recharge them alternatively. In Jio I recharge 1 number for 84 days and then as soon as it expires, I recharge the other for another 84 days. In this way I keep both numbers active, because I don't exceed the 90 day period boss. Once you exceed the 90 day period without recharge on your number, you have good chances of losing out your number. So I at all times get Incoming calls and SMS in Jio on both my numbers (1 active + 1 inactive (no recharge) at all times) which I believe is the main reason of even keeping a phone at the first place, that one should receive a call/text.
Consider all these points before porting & don't be penny wise and pound foolish like me & then eventually come back to Jio.