Firstly, welcome to the Community!
What phone do you have? Can you confirm the current software version?
Are you able to get in touch with the Samsung Pay team who can be reached at 0330 SAMS PAY (7729)?
The query is regarding my sons phone, he has a Samsung S7 running android 7.0 on the Vodafone network, we have looked a bit deeper into the problem and it appears that Samsung Pay thinks it is actually Swiss not German, we have performed various resets to clear all memory cache's and restored to factory defaults but the problem still exists. There is a funny thing, when you perform a reboot to factory defaults, the phone prompts you to enter select the language (e.g. English UK) but the prompt about loading still appears to be in German. One the reboot has been completed, everything is in English except Samsung Pay.
I have an identical phone (Samsung S7, running Android 7.0) on the vodafone network and mine appears to be working fine. However, there was an unusual situation because my phone upgraded automatically to Android 7.0 but my sons phone seemed to take at least a month before it recognised the upgrade to android 7.0.
There also appears to be a problem with the fast charge on both S7's and my wifes S7 edge, when will this be fixed because I thought that something like this would a priority, especially after all the bad publicity with Galaxy Note battery issue.
It appears that we were supplied with a foreign phone, downloaded the app PHONE INFO off google play, which confirmed that the phones CSC code was programmed so that the phone thought it was a swiss phone.
The phone was still under warrantry, so we returned to the supplier and it was replaced with a UK phone.
I believe the phones CSC code can be re-programmed but we didn't have to go down this path.
Hope this helps