I'd suggest you do as the supplier has asked a be patient... Customer service is not a high priority in the Germanic speaking world, so think in weeks rather than days and hours. They will take their time and check every detail along the way, but in the end I'd expect that things will be sorted out. Up to this point in time the supplier has followed procedure, making the claim etc... if he really was intent on cheating you, he'd simply have ignored you!
If you have not heard anything from him in a few days, send him a reminder, but I'd only start getting worried about this in a week or so if it had not played itself out by then.
Jim2007