WordPress in ipage.

I recently bougth the ipage host service, so Im new in online hostings. I have 3 domains now, one from ipage(comes with the plan), one of godaddy and one of 1n1 sites. So I installed wordpress in the first one ipage domain and it was running, now I connect those two like “add domains” and installed there wordpress, before I replaced the DNS. After I tryed to erase the ipage domain and it can not be possible and clicled on “erase from the list” Now I cant reactivate that ipage domain and those others two domains are showing the that page of the site where I bougth, I do not what should I, can I restart everything and put everything clear?? an other the ipage domain is showing 500 internal server and when I try to check in mojomarket to reinstall wordpress and the result is this: “We were unable to check the directory you requested. In most instances, the .htaccess file is the reason for this. You can either update your .htaccess file manually, or we can move it for you.” I cliced in move it for me and the result is the same. Please what I should to do??