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 someone a gift.
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, cancel the transaction for nonpayment after four days to give the "buyer" a strike and prevent feedback from being left. Set your Buyer Requirement to reject bids or purchases from users with two or more strikes.
You should probably ignore anyone who requests your text or email unless they actually make a purchase. eBay will eventually remove a 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.
To contact eBay, you can use the Help & Contact link at the bottom of the page to request a call back from eBay. Use the "Contact us" link and follow the prompts for your issue and you should eventually wind up on a page with a chat option. Choose that, and the last option that appears in the chat window -- use the "See more" option -- should be "Contact an Agent" to request a call-back if you are in North America.
https://community.ebay.com/t5/Selling/How-do-I-contact-Customer-Support/m-p/32016431#M1783851
