If I were you I would just bury this idiot with mails. Again and again.
I have tried this with a german e-shop who just didnt send the product I had paid for.
For a week I just posted about 10 mails every hour. Again and again.
And I then researched the board of the shop(owners) to find their personal mail adresses.
And I can promiss you they got mails too. Tons. Asking WTF was the matter.
In the end the product was suddenly delevered at my doorstep
Begging me to stop mailing them