Kobalt IS lowe's, return the files. At worst you'll get store credit. Don't bother with any detailed story. "I was not satisfied with the product."
If you have the receipt or you used a card and it's inside the normal return period then you can get cash back. Any other circumstances, just bring them in and return for store credit. If they give you any crap ask to speak to the manager on duty. If that doesn't get you anywhere, make sure you've gotten names and ask to speak to the admin manager or store manager. Trust me, they'll take them back, it's policy, but sometimes you get a few idiots in the way first. It really depends on how much theft and fraud that store has to deal with. The worse it is the more stupid they get about returns.
This is the first I have heard about the files being lousy, but I haven't heard anything good about them either. When I worked there I don't think I ever sold any. We did sell the nicholson's regularly when we carried them. People who buy files in this day and age tend to be a bit more traditional or quality oriented for their tools.
Kobalt in general runs from lousy to excellent. As already pointed out, it's an outsourced product no different from Craftsman and Husky. Some of the tools are very good, but it does vary. The nice thing about it is that for the vast majority of their products, if anything ever goes wrong with it you can bring it in and they'll do a refund/rebuy for the current equivalent. Break a 16oz hammer faced, wooden handled claw hammer? Bring it in regardless of how long ago you bought it and get the current version or next step up if they don't have something equivalent on hand. Over extend a tape measure? It stopped retracting after getting dropped in the sheet rock mud? Bring it in and get a brand new one. I sold a lot of contractors a matched pair of tape measures. They'd use one and keep the other in their truck. When the first failed they'd get the replacement out and keep working, then swing by the store on the way home or next time they had to pick up more supplies and exchange it for a new one. Until they lose them they'll never have to buy a new tape measure unless they want something different.
