Hello Shaber53,
Did you get any errors while importing the file in to Method? I tried to reproduce it on my account, I created two fields in my Customer Table and then I imported data in those field based on Update existing records by matching the key fields in Set option and selected Name as a Key field and then Click on Import data. Import was succesful and data was present in my customer database. Can you confirm that you used the "Update existing.." to update those fields while importing data in those fields. If not, try it.
If the issue persist, please call on our support line 1-888-925-6238 option 2 for support, or email us on Support@method.me and we can look into the issue.
I hope this helps.
-Inder