Everything you say is nonsense.

No one will say that their products are not good

The most practical and simple thing is to ask him directly how long the warranty period is if he buys a large quantity. What should I do if I exceed the warranty period?

You must buy it, but verbal proof is not enough. It's best to fax the contract of the ball, which is stamped and written in black and white, and ask him if he has insurance. If so, I'll show you the insurance certificate.