Custom domain redirecting

can anyone help I brought a domain markymouse.store and changed my ns1 and ns2 to infinityfree.com in namecheap went to add a domain in infinityfree add domain followed all the steps and found my the dns but said the domain was not populated yet this was after 5 days today i saw i have a alias on my account so added my domain to that and it worked fine how ever when i went to markymouse.store it took me to markymouse.music.infinityfreeapp.com so i have removed the domain from that account