Well they need to say that on their website and they don't so I expect 3 BTC which is what I paid. Do you have a law degree?
I don't have a law degree, but I was recently reimbursed by my Swiss employer for my expenses abroad. They paid me Swiss Francs with the rate on the day of the expense. I'm pretty sure it is legal and I'm also pretty sure you are getting Czech Crowns if you ever get a refund. Does your lawyer has a Czech law degree?
That said, I'm still willing to pay you 330USD for the device.