It's not the seats that makes the ticket refundable, but the ticket type Plus, which gives a range of benefits, including seat selection of the comfort seating area at the front of the economy cabin. So long as you cancel the Plus ticket more than 24 hours from departure online, you get a full refund, if you call up then there's a US$40 charge.

https://www.flytap.com/en-gb/manage-...efund-policies