Can I disable customers making backorders purchases on my FBM listings?

We use a 3PL company to store and ship our FBM listings. We recently sent 48 units of an ASIN, their company confirms receipt of 48 units. However, 53 units were sold with one customer buying 5 units yesterday when we had nothing available.

I thought perhaps the company listed 53 units available by accident instead of listing 48, but the company said that wasn’t the case and it’s a setting on Amazon that I have to change to prevent customers from buying items that not available and causing backorders.

Is this the case? I’ve tried to look for this setting but haven’t been able to find it.