Any way to prove that a customer has ordered ?

[Alexenn]

Hello,

 

I have a shop with prestashop 1.6.1.4.

I'm using a module in order for my customers to pay their orders, I had to set up that module so that payments are automatically accepted by that module.

The problem is, for an unknown reason it has been reset, so the payments have never been accepted and expired after few days and I already sent the products.

But now, I need the customers to pay again, and some are acting like they never ordered on my online shop.

The company distributing this module doesn't seem to be able to do anything.

So I want to know, is there any way I can prove a customer has ordered on my shop ?