Multiple Problems With WordPress and Themes

I set up my website with WordPress and Cpanel a few weeks ago and have been experimenting with different themes. I decided to go for a premium theme after a while and to my shock it didn’t work. I went to Log In to WordPress to purchase the theme and it told me I didn’t have an account, although I had my account open in another tab.

So I created a new account and then found out I had to pay to get my domain name mapped on to the new account, which I did, and then I purchased the theme. I now have two WordPress accounts for the same domain and the theme that I paid for is not working. Even if I hit “Save and Apply”, etc. the new theme won’t show up when I go on my website, it shows only the themes from my first WordPress account. I’m also having problems with the Customize toolbar; I’m using Google Chrome and Windows 10 yet the menus in the Customizer are all cut off/missing and many times the Customizer fails to load and I get an error message.

I have no idea whats happening and I’m truly hating WordPress right now, please help!