Customers invoice are only able to pay a partial amount why is this happening?-- We then have to create a different invoice to get the balance paid-please advise

Good Morning, @karol2. 

It's great to have you here in the Community. I can give you some additional information to help resolve your customers invoice. To better assist you, is this issue happening with one customer or more than one? If more than one, then I recommend using the Verify and Rebuild Data tool within your account to check for data damage.  

Note: Always back up the company file before using any tool in your account. 

Verify Data

1. Go to the File menu.
2. Hover over Utilities. 
3. Choose Verify Data. 

Rebuild Data

1. Go to the File menu. 
2. Press Utilities. 
3. Select Rebuild Data.
4. The tool will start as soon as another back up of your company file is finished. It may take some time to complete. Hit OK, once you get a message saying, "Rebuild has completed."

If only happening to one customer, then I suggest merging the customer with a new one to remove the error that is occurring. Here's how: 

Merge Customers

1. Locate the Customer menu. 
2. Pick the Customer Center. 
3. Take note of the customer's name that you'd like to keep. 
4. Right-click on the customer you'd like to merge and press Edit Customer: Job. 
5. Replace the customer name and select OK. 
6. Choose Yes when prompted to proceed with the merge. 

If you have any other questions, feel free to ask. I'm always here to lend a helping hand. Enjoy the rest of your week! 

Thank you- Our data has no issues, and there is only one invoice for the customers that this happens to. Just the other day--I invoiced someone for their balance and they only paid a partial amount and said that is all it prompted them to pay, and then again today she told me that was the only amount it would allow here to enter?   So ,.. still have no idea what is going on

Thanks Candice, I tried that,.. Our file data has no issues- and the customers I have had the issue with only has one invoice and there are not multiple names of the same customer.  Just the other day- I requested a balance paid and he paid a partial amount stating that was all it would allow him to pay--so annoying. Then yesterday-same thing--she stated that was all it would allow her to pay. So I have no idea how to solve this-except to create a new invoice with the balance--which is crazy.

@karol2 Thank you for joining community!

Based off the information you provided, there may be a manual payment recorded against the invoice altering the online balance.  When this happens and your customer attempts to pay the balance in full, QuickBooks will adjust the amount for payment.  

I would advise you to look for a manual payment on the list of transactions for that invoice, remove it, and resend the invoice. Your customer should be able to pay the balance in full.

If your customer continues to have problems making the full payment our chat support can help troubleshoot further.

This link will take you to the QuickBooks support page, where you can select your service and the proper contact channel: Contact Support

Let me know if that works for you.