i tryed to have a look in the server store and it said my minecraft name doesnt exist... and im pretty sure i wrote my name good i tried it many times:
Try the little drop down menu that is shown there, sometimes that will help. Also, make sure it's not spaced out or has any capitals (if it needs them)
Are you sure? because on the drop down menu it looks like the name has no space in it compared to what you have typed in.
There is currently a problem with the Buycraft service. We have already notified the guys over at Buycraft and they are working on a fix. We hope that it will be fixed by tomorrow, sorry if this causes any inconvenience.