when someone does the @name thingy i got the donation and changed my color then the old @name things kept the old color? Like if someone did it now it would be @Sewiferos with the gradient

I have no idea what you’re talking about. Your name looks fine to me, it’s SewiFeros with the green and orange gradient I believe.

CTRL+F5 to clear your cache if something isn’t updating on your end.

No the old post still have the old color

That's just how the site works. The @ isn't an image that permanently points at what your name currently looks like. The post formats it to look like what your name looks like when the post is made. It won't get updated when you change your name or its color because the formatting is already done.

You could try editing your post if it is really important..