Thanks for your help.
There was confusion when try all the themes Live Previews before installing, then all the theme customization options are visible at the time of customization. But MyThemeShop theme is not like this, but after activating the theme, Appearance >> Theme option comes, there is the whole setting of theme, this was later revealed.
1. Suppose I bought a theme or plugin and it expires after a year, can I continue to use that theme or plugin even without renewing it, or will I have to pay?
2. Do I have to pay separately for support?
3. If I buy a theme i