Buy.at's International Sales Policies
I think Buy.at should let affiliates know in advance that if anyone makes a purchase that is not in your preferred currency that you need to either accept a paid option via Payoneer Debit card (after you generate at least $35 in commissions in that currency) or wait until you somehow generate sufficient commissions in that other currency to receive your commissions in your preferred currency. It may be years before I generate $250 in commissions in GBP£ ( since I don't target UK buyers) so that I can receive any commissions for any sales in GBP. Worse if the sales are in CAD ($450 minimum to convert to USD)
Penalizing affiliates for shoppers' actions that they have no control over is not affiliate friendly.