QB Issue Resolution:

delete the bill

now there is a vendor credit as there should be, contact the vendor and ask for a refund, or leave it as a credit that you can apply to future orders – I would call either way and insure that they also have the credit posted to your account.

Resolution for Issue 'Can someone please help with a cashed voided check?' available: Yes (Solved).
Source: Intuit Community forum.

Can someone please help with a cashed voided check?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for a refund
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for a refund [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.

Get 50% off Quickbooks Online

Click Here for 50% off!

Additional Support Options: