I have never heard of a ceiling fan with bad bearings, and I don’t think you can just drop them in. You need a new fan if the bearings are bad.
Could it be a bad motor caused by using a light dimmer on it? That will destroy any ceiling fan motor, causing it to hum. No fix for that except replacement.
Bobf is right about that. if you have the manual, call the 800 number to see if they can help, if you don’t have it, talk to the Home Depot where you got the fan about a number.