So basically they have completely stopped DCB issuance under Alumni program. If u applied under that, it was LTF hence the executive mentioning that.
Also, to clarify, the mail is saying - can’t give u DCB alumni. If u want DCB metal, send us all the documents and we shall review your request and upgrade if it meets criteria.
If you have good relationship with the bank, you can apply and they may issue it as paid metal DCB.
If u can meet spends for fee waiver and are a traveller, it’s decent card.