Is anyone having issues having passwords remembered by APPLE -

This is driving me CRAZY -

I can loggin to my iphone but not my APP STORE account. I've changed the password 5 or 6 times and each time it lets me login to my phone but not my app store account. Then when I try to change the password to the appstore it won't let me use the new iphone login because it's already been used.

Give me a break!!!

I really hate certain elements of APPLE and this is ONE OF THE TOP 2