A message that says "I am interested in your item, kindly text me", an offer greater than your buy it now price, or a request for a gift card is generally the start of a scam where the scammer winds up sending a phony payment email that makes it look like the seller has received a payment when none has actually been received. Scammers like to target new sellers, particularly those selling expensive items.
Sending contact information (text or email) prior to a transaction is a violation of eBay policy; this policy is designed to protect honest buyers and sellers from this sort of thing, and to prevent off-eBay sales.
Never buy a gift card for anyone unless you are giving them a gift.
You should probably just ignore anyone that sends you a message requesting a text unless there has been a purchase made. As a seller you should always check your account directly (not following a link in an email) to see if you have actually been paid prior to shipping. If an actual buyer does not send an actual payment, file an unpaid item dispute (or whatever the current cancellation for nonpayment process is -- eBay has recently changed things) and go through that process to get your fees back and to give the "buyer" a strike -- and set your buying requirement to reject bids or purchases from users with two or more strikes.
eBay will eventually remove the scammer's account, but the scammer will just create a new one or hijack an old one and continue sending scam offers and messages. Sellers must remain wary of any user that wants the seller to violate eBay policy.
You can avoid many common scams by listing your item for a fixed price with immediate payment required and by not accepting any offers. That way the buyer must complete checkout and actually pay in order to proceed.
