I just bought the app against 1$ two days ago, your software/app is not letting me add a vendor, it wants me to renew may payment why

This is not the impression we want you to experience where you are unable to add a vendor to your newly purchased QuickBooks Online (QBO) mobile app. 

To better isolate the issue, we can access your QuickBooks account through the web interface. If you can log into your account without issues, let's perform some troubleshooting steps to rectify the mobile app issue. The QuickBooks Online (QBO) mobile app is always in sync with the web version. It's possible you have an out-of-date version of the QBO mobile app and it is necessary to update them to have access to new features and fixes. Here's how:

1. Open the App Store/Google Play Store on your device, then tap your profile icon at the top of the screen.
2. Find the QuickBooks mobile app in the Available updates section.
3. Select Update.
4.  

Also, when the app's storage data is almost at its limit, it causes odd behavior where you are unable to vendors on the app or requires you to renew your tour subscription. To resolve this, we can delete the cache from your application to use it again with a clean slate and all of its capabilities at your convenience. Here’s how to do it on different mobile operating systems:

iOS:

1. Go to Menu ☰ and tap Help & Feedback.
2. Tap Refresh Data.
3. Note: A message appears “Caution. If there was a problem getting your latest QuickBooks Online data, you can refresh it now. It may take a few minutes.”
4. Tap Refresh to confirm.

Android:

1. Go to Menu ☰ then tap More Options ⋮.
2. Tap Settings then Refresh Data.
3. Tap YES to confirm.

Also, I'd suggest restarting your phone. If you continue to get the same result, uninstall and reinstall the application to start fresh. Follow the steps below to delete it:

1. Tap and hold QuickBooks Online on your phone.
2. Drag the app to the Uninstall section.
3. Press Yes to confirm.

Additionally, here's an article to learn more on how to access QuickBooks Online on your iOS (Apple) or Android devices and for the best results on your mobile device when using a browser: QuickBooks Online access for mobile devices.

I'm just one reply away if you need assistance when doing tasks in the mobile app such as accepting matching transactions in QuickBooks Online mobile. Take care always.