Copy of electronic boarding pass - how?

I need a copy of an electronic boarding pass for expenses claims. The boarding pass (for a flight done 10 days ago) was sent as an sms and got deleted a few days after the flight. I phoned Brussels Airlines customer service, was told to send the request by email and then got the email reply that they don't do copies of boarding passes. Is this normal? They cannot resend an sms? The flight is registered in the Miles and More account and it was in the past anyway.

Can they do this? It's not that electronic passes are unique originals - you can print them half a million times if you want to (I usually print them 3 times). Any advice on how to get them to send it again?