Ibibo Group / Goibibo — Promotional SMS

I want to unsubscribe from GoIbibo's promotional SMS, but there's is no way to do it. They don't have a support email id, nor do they connect you to a customer service agent on their Customer Care number.
I never signed up for their promotional SMSs.

The following link of Goibibo's website shows that they don't want to give people a way to unsubscribe from their "Promotional SMS harassment" lists. In the following link, they said "We're still working on the feature" that would allow customers to unsubscribe from their promotional SMS lists, but the interesting fact is that this was said by them on "Tue, 21 Apr, 2015". That's right, 2015!!!

https://support.goibibo.com/support/solutions/articles/[protected]--subscription...⇄