Pure lies. Don't fall for this scam by Axis agents.
Firstly, they are likely agents who get a commission for new cards, but not for upgrades. If you want to check if you are eligible for upgrade, contact Axis directly via phone or chat and ask if you are eligible for any particular card.
LTF upgrade is impossible (from what I know). Just forget it.
Secondly, what those scammers / agents told you is a lie or half truth. They tell you that it is an upgrade, but it is actually a new card. You can again verify this by getting in touch with the customer care and by asking them how long you can use the existing card if you proceed with the upgrade. They'd tell it is
only for 45 days, after you upgrade that takes hardly 10 minutes as it is done over OTP initiated by Axis. This OTP will clearly mention that the OTP is for upgrade of your existing card to whatever the new card is (for example Axis Ace). The OTP initiated by agents will only contain generic info something like this is the OTP for the latest application (and do not share with anyone), but you will be forced to share this, if you proceed with the scammers.
When I had some l leisure time, I played with those guys / girls and got to know how they scam. Don't fall for it. Report them in Trai DND app, block them and fill the following DND form too...
To ensure that you may not receive any unsolicited commercial calls please contact your telephone service provider for registration in the National Do Not Call Register of TRAI.
www.axisbank.com
You will stop receiving the calls from agents in appr a month after doing all the steps.
If you still receive calls, send an email to nodal officer and then after sometime to RBI. Most bank people including agents are scared when they hear the three letters (RBI).
If you still want to ignore this post and want to proceed with those Axis people and if you have plenty of time, go ahead and get everything in writing (not WhatsApp message), using an official email address. When things go wrong, you need written proof to show to RBI. Courts may take WhatsApp messages and recordings, though. RBI has faster mechanism to solve most issues than a court.