I never received my October Weekend 40k badge and am a bit miffed! Anyone else in this with me? How do I get it added?
Could you share the activity with us so we can have a look what might have gone wrong?
Ok. Date, distance and activity type looks good. The device should be no issue. It is not particulary old. The risk with older devices is that they do not save the files in FIT format which is a requirement. Easiest way to check is to click "Export original" and see which file is exported. If everyting is ok you should get a zip file with a fit file inside.
Have you double checked that you have joined the challenge? https://connect.garmin.com/modern/challenge
It should be in the "Current challenges". It stays there 1-2 days after the challenge has ended.
I think it is too late now to do anything yourself. If you see that you don't get a badge you should right away do a couple of edits to the activity. Every time you do an edit to an activity it will be evaluated for the badge. For challenges you got until noon the day after the challenge has ended to do anything.
Now you will most likely need to talk to Garmin Support.