[Resolved]  Indigo Airlines — mysterious change in flight schedule

Address:

House No 239 Sector 15, Panchkula, Haryana, 134113

I have booked return flight tickets from new delhi to port blair starting on 2 january 2020 pnr no gdspvv.
Later due to operational reasons flight schedule was changed and i had to choose alternative flights (By calling at customer care) from 1 january and i changed my hotel booking accordingly.
Two days later i got a sms notification of some different flight schedule which i never choose. I checked on indigo site with my pnr number and it was showing the flights which i choose so i ignored that sms.
Today after one month i got the same notification sms and when i called customer care they are telling me that i only have changed my flights online to the current schedule after changing them telephonically and they cant correct it without conversion charges.
My point is
A) i have never done any changes after telephonically accepting the altered schedule
B) how could you allow such a change online without charging conversion fee after i have done the changes telephonically.
Now i demand that my flight schedule should be changed to previous one as fixed telephonically.