I find nothing special in actual about Imperia over preferred.
But on one occasion, Cluster head and Zonal head visited my work premises because I am an Imperia customer and the discussion with them helped in fetching Infinia.
If automatic upgrade doesn't happen you can request your RM to do it for you.
- Classic to preferred RM did it for me.
- Preferred to Imperia Auto upgrade happened.
If they are not responding and doesn't care about the business you offer try reaching out to Cluster Head/ Zonal or Circle Head, you will get these details from the notice board of the branch. They will definitely help.
Else send a mail to premium services mail ID's (Preferred/Imperia) or MD...
Metro Pincode - Wealth card more than 5L CL on Axis, HDFC, Amex cards
Non Metro (Tier 2) - Select card irrespective of bank (CL above 2-3L)
Rural Pincode - Wow card (Secured or sometimes Unsecured)
There is one hack you can DM me.