I would check with the company and see if it is still under warranty.
They may cover the repair if you send it in.
If not, or the repair costs seem unreasonable AND it starts making noise again (it will eventually):
1) You can continue to try to lubricate the bearing surface.
2) Replace the fan with a computer fan of the same voltage
3) Buy an upgraded unit from Concertone
4) Replace the entire unit with one from a different manufacturer.
I personally do not recommend one course over the other; that is totally up to you. What I would do is call them and see if they will make it right either under warranty or a reasonable cost.
They may surprise you. (or not but at least you will know)
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW