Safe-T Claim Issue

I sent a customer in Italy and item, tracked + she raised an A-Z claim and was refunded. The day after she got her money the tracking showed it was delivered.

Amazon do nothing to help - and the customer ignores me when I ask for the money back or the item

Im a small business + out of pocket for the postage & my item

Amazon said to rase a SAFE-T claim, however I have tried to do so 2 weeks , tried laptop, PC and phone to raise - Safari & Chrome, tried clearing cookies but constantly getting message

Internal Error

• We’re sorry but we encountered an error while processing your request.

There is a time limit of safe-t claims, so time is against me & amazon customer care is hopeless at helping me

Does anyone have any experience of this? and how to fix?