I want to let you know that I'm here to help you. I know the importance of having the ability to search for customers in the customer's search bar in QuickBooks Online (QBO), Helen.
Since you already uninstall the app and then reinstall it, I suggest reaching out to our Customer Support Team. They have the necessary tools to check your account in a secure environment and help further investigate your concern.
In the meantime, we recommend using the web version while the issue is being worked on. Here's the link: https://quickbooks.intuit.com/au/.
In addition, check out this article as your reference to guide you about the QBO app features available on supported mobile devices: Compare mobile app features.
I'd appreciate any additional details you can provide so I can help you out with your concern about the customer search section that has disappeared. I'll be keeping an eye out for your response to this.
