It is a well known thing, that ChoRCom blocks the SMS from 1901 (the response SMS with UPC or Unique Port Code after sending SMS to 1900). But once we call the CC, they will tell the code verbally, at least.. If they are still NOT giving you the code, then its better to complain them on pgportal, saying "RCom blocking PORT sms"..
There is a reason they are called as ChoRCom. They have the cheapest tariff plans in industry (even cheaper than Jio), shares the JIO 4G network, but still, they are the NUMBERO UNO in losing customers every month via MNP (that is even after blocking port SMS). Because they are Chor.