It seems you are using a Basic License, which is limited to 40 minutes per meeting. To be able to enjoy longer meetings and additional features, please purchase a license.
Although you have paid for an upgraded account, it sounds like you have not actually assigned the licence. Zoom does not do this part for you. You will need to act as the account admin and assign the upgraded licence to your account.
In the Admin section click User Management, then Users. Using the search bar locate or search for the user who you want to assign a license. (Your own account) Click Edit at the end of the user row. This will open a window. Choose the User Type to assign.
After choosing the User Type (Licensed), select the license. Click Save.
The license is now applied and you can use it immediately.