My First Money Order

My energy provider is Bohemia Energy.  I switched to them about three plus years ago and they've been fine.  Every three months they send me a bill notification to my mobile.

Apparently I overpaid and I received a rebate.  Czech Post delivered a money order to me for 351 Kč ($16).  The money order is only valid until 18.5.  

Many people use the Czech post office for financial services to the money order wasn't that weird to me. 

I don't understand why Bohemia Energy just didn't give me a credit on my next bill.  That would have been more convenient for me.  Or if they wanted to pay me back the money then they could have asked for my banking details so that they could have transferred the 351 Kč to me.  Instead, they paid the post office to deliver me a money order which gives me a limited period of time to collect.  I don't know what would happen if I didn't cash it in time.  Does the money go back to Bohemia Energy?  Or does Česká Pošta keep the money?  

Update:  It took me a few minutes to figure out where in the post office to cash it.  Once I found the correct window I had my money in about five minutes.

This was my first Czech money order.  It's incredible to me that after almost 12 years here in Czechland I'm still having new experiences.