So honestly I don't want to destroy my HDD just yet, what happens if they refurbish it? Is my data vulnerable?
Microcenter does not "recycle it" on their own.
They hand it off to a wholesale "recycler".
They hand it, and a bunch of other stuff, off to the next level guys.
...
...
Eventually, the drive with your precious data ends up in a HUGE pile of crap, on the side of the road in some 3rd world hell hole.
A 9 year old will pick through the stuff, looking for anything remotely "working".
It will be sold for the equivalent of $0.03, as part of a lot of 1,000 theoretically working drives.
Eventually, it may end up in a different system on the other side of the planet.
Or, it may be dismantled for rare earth fridge magnets and its precious metals.
But once it leaves your hands, you no longer have control.
If you are concerned, either take it apart yourself, or just drill through the platters.