My son cannot log into his account

I am having issues with Khan Academy not letting my son login to his account. I've reset the password a half dozen times, and it keeps saying the email or password is invalid.

I tried finding an email address for support, only to find that there isn't one, and I can 'ask the community' for help, or search through the troubleshooting info (which was absolutely useless).

The only help I was able to find, was in other posts saying to try another browser, which in and of itself stretches the bounds of absurdity if I cant use the built in broswer in EVERY SINGLE SAMSUNG MOBILE DEVICE.

I am finding Khan Academy to be much, MUCH more trouble than it's worth, especially after talking to my son's teacher and finding out how bad the issues are when parents try to connect to their child's school account (which I wont even attempt, knowing how difficult it is to get him into the account we JUST created for him).

Truly poor usability, and aggravating that it should be such a pain.