Looking for advice on the following lost bag/reimbursement scenario:

We booked a United award ticket that originated in the US included an SAS connection via Copenhagen to Stuttgart to arrive on 7/7.

My checked bag did not arrive in Stuttgart. We went to a wedding in the German mountains about 3 hours away. On the way we stopped at Edeka and H&M to by toiletries as well as clothing suitable for the wedding. This totaled 173.67 Euros. SAS returned the bag to Stuttgart airport on 7/8, however the agent at the airport advised us that it would be difficult to deliver it to our location and to just pick it up on 7/9 when we transited back through Stuttgart, which we did.

I filed a claim with SAS asking for a 173.67 Euro reimbursement. SAS responded stating that they have decided that 75 Euros a day is reasonable and they will only reimburse 75 Euros. I've responded that this is not reasonable at all given the circumstances and that we not only had to buy toiletries but clothing suitable for a wedding - additionally we didn't get the bag back for two days. I think I was very reasonable in the fact that I went to an H&M, the cheapest place I could find, to buy clothing. I think they should reimburse the full amount. Of course, they are refusing.

I am thinking we could potentially file a DOT complaint since this is a US PNR that originated in the US (even though SAS only had one segment from Copenhagen to Stuttgart), as well as German and potentially Danish aviation authorities. I'm also thinking of the small claims court route - I think that I could argue for US jurisdiction because the flight was a US ticket that originated in the US. I know it's only like 100 Euros but I am upset, and willing to fight. I welcome any advice!