Computerisation 2 aborted test issue

Had an mot test in, entered details - came back with too early to test and the date was over 2 months left on the current test.

So before I carried on with test I tried phoning customer. no answer, so I aborted the test,

but the vt30 that the computer then printed out was a totally different registration number and vehicle !!!!

the vehicle on the one printed out had never even been at our garage before

The customer phoned back to say his mot definitely runs out today
I then checked the DVLA database & it shows that the customer is indeed correct.

So I then did the test

What's going on?
I'm trying to be helpful to the customer by saying that he had 2 months left to run on his mot, but the computer is making me out to be a liar!!

Checked my test logs for the day, it showed that I Aborted the one with the wrong reg. How on earth would I know Reg & VIN of a vehicle that had never been on my premises?

PS I've kept all screenshots of this issue to show to DVSA when they are not busy.