Ok, let me understand more clearly on this? You say it doesn't fit in the port or does it not fit tight in the port where it is loose? And did you get this charger at the sprint store or is this an after market accessory? And if it was purchased within 14 days, you may be able to go back to the store where you purchased and get a refund or exchange.
I would follow raylitherland67's suggestions. I have the Evo3D and my HTC and non-HTC chargers all fit tightly. Also, make sure you using a micro-USB instead of mini-USB.
I've had multiple chargers including my old Blackberry one. Some connect more securely than others, but all of mine work. My HTC one works well, but it's funny, my old Blackberry chargers fit even better. If you buy chargers on places like eBay for $2, I wouldn't expect much.