Wheel issue and time crunch- thoughts?

I'm in a bind. I have had my rear wheel (a stock semi-aero alloy rim that is stock on bike) at the bike shop for 2 out of last 3 weeks trying to fix a hub/bearing issue. It's a Felt tri bike and this is the stock Felt TTR4 wheelset with only 2,000 miles on it which I really like and they hold true and roll fine even if a bit heavy. I'm not in the market for $2k carbon rims....

So first they replaced a race in the main hub and rebuilt it with new bearings, which didn't fix the crunchy noise (kinda catchy, light grinding bearing noise sound) issue that came back after a short ride. Now they say it is the bearings inside the hub. There was a miscommunication and instead of ordering replacement pars for just the hub, they ordered me a new cheap rim and hub for $200. They are afraid that even if they rebuild the hub (one that spins in the freehub assembly) that it is still going to have the issue unless I get a new rim. I fly out of town for Ironman Florida next Tuesday so have about 2 business days to make something happen. I'm not happy at the current situation. I do have decent road rims on the bike which I guess I'm going to being cruising on and I don't really want to rent carbon for $200.

So I guess my question is, do I buy the argument that my wheel is likely not going to be fixable if they rebuild the freehub? They said that likely the spoke tension wouldn't be even after the rebuild and would have issues with it. The bike shop is reputable but I've not dealt with these guys specifically before, nor have I had this kind of work done before. Not sure what to do at this point.