Autocorrect changes itself back
So here is something extremely annoying,
A few months ago I had the super clever idea to add words to my autocorrect. My name is Tobi and I thought typing the whole name is a lot of effort so why not just "to". In German, this makes sense but ever since I moved to the USA about half of my "to"s are "Tobi" and that *****. A lot.
I'm not stupid, or so I thought - I changed it back on the phone and to be sure also on my macbook. One time while online. One time while offline. No chance. Everytime I change it, is miraculously changes itself back and again I have to search my emails and messages for hidden "Tobi"s.
It sounds funny but it's not. Please help.
iPhone 4S, iOS 8.1.3