For each batch you buy, keep the paperwork and the supplier's details, and don't buy goods priced well below market: when an employee buys fakes, the owner is the one convicted

In plain words

Selling fakes is enough for a sentence of up to 3 years if you earn 30,000 CNY or sell 50,000 CNY worth. Goods left unsold in the warehouse also count. "I didn't know they were fake" is not for you to decide: if your purchase price is clearly below the market price and you can't explain why, you will be found to have known. Keeping the purchase contract, invoice, payment record and the supplier's details is what leaves you a route to avoid paying damages.