I see no problem with it being a bitcoin payment, it was for a dollar amount. No different to me making a transfer to his account in UK Pounds and his bank transferring it to US Dollars.
I would consult with a lawyer if you paid in bitcoin. But as far as i know its not recognized as a official currency in US.
It is in Germany, and most things that the German banks do are reciprocal to some extent in the US. Also, the US has recognized it as an asset, which can be translated to dollar value in courts. I would think that you could push for it's CURRENT value if not refunded in actual bitcoin. I am not a lawyer, though highly interested in law and married to one
YMMV.