We are pretty sure that a previous supplier of ours was running their machines on a competitor's (of mine) dime and billing them for materials/goods and burying

We are pretty sure that a previous supplier of ours was running their machines on a competitor's (of mine) dime and billing them for materials/goods and burying it in the sales sheets, while shipping us the product that was near-identical to theirs but with our logos and branding on it. I understand this is fairly common when making knockoff goods, too.