incorrect invoice sent to my customer

Hello,

Last week I sent an email invoice to my customer as usual but they responded that there was an obvious problem with it. I checked the invoice in my system and it was correct. 

I asked them to send the incorrect invoice back to me which they did. The details on the invoice are not right. There is a completely different invoice number style, a completely incorrect customer - not even one of my customers at all, and there are no line items listed.

My details on the invoice are correct: name, business details and payment details.

I have since resent the customer their invoice and it arrived at their end correctly.

What are the next steps for this? I notice that this problem is mentioned in the community forum as something that can happen, which is concerning. It is the first time it has occurred to me.

Thanks,

Kylie