Somehow I doubt buying this card back in October of 2016 was a mistake
It was actually a free card anyway
You were given the credits as a signup bonus of sorts
Sounds more like you're wanting to trade this free card in for a new free card
You would need to contact customer service about getting a refund for the free credits you used to get a free card that you've had and have very likely been watching for about ten months now
Good luck