Is it possible to demagnetize RFID (Mifare), especially with a phone?

Question

RFID

Yesterday I was puzzled in the subway. I glued the so-called "Plantain" card, which uses RFID, to the phone case, when the cashier replenished the card, she shouted that it would demagnetize like that. I was surprised, they say, how it is, it’s at radio frequencies, not a magnetic stripe, but I wondered if it could, at least being close to a smartphone.

Answer 1

no, it won't demagnetize

Answer 2

In the event that the card stops working, this will be an argument not to restore the paid validity period to you. And so - nothing threatens the card.