is an automatic liability violation of law. It's like a traffic ticket. Infringe, and you're liable, no matter what your intent. Innocent infringement is grounds for a court to reduce any damage award -- but, you can still be sued for infringement damages.
Consequently, there is absolutely no way that you can avoid liability, other than by not selling infringing materials.
Legally, if you haven't made a copy of the music, or the discs, then you haven't directly infringed. However, you could be held to have committed "contributory infringement," because you are aiding the distributors in the commission of the infringing acts.
If it were my business, and I believed that some of the materials were infringing, I would contact the purported copyright owners and ask them if the music is licensed. Until receiving confirmation, I would not sell the materials. A copyright "takedown" notice on the website, is always good business practice. However, the physical sale of a disc cannot be protected by the takedown notice, because only digital/intangible activities on the internet are covered by the Digital Millennium Copyright Act (DMCA
You can certainly take your proposed path, and sell until you are told to stop. But, if you get caught, you could be in hot water.
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