Credit Card Rates, Fixed?

Well, I switched from worldpay to my bank. Initially (for about a year) we were at 2.4-2.7% but the past 2 months have risen. Last month we were at 3%. I’ve been tracking it and emailed my rep. He brought up the idea of a “Fixed Rate”. I’ve never seen this as an option anywhere and am a little unsure if they’re trying to do something to help or to screw me over. Any thoughts on this?