QB Issue Resolution:

You will have to call support and they will help you exchange. USe the Contact Us link only to find the proper phone number – DO NOT call any phone number openly displayed in a post or comment as those are 99.99% scammers

Resolution for Issue 'I need Quickbooks pro 2019 for Mac but accidentally purchased the PC version. How do I change this?' available: Yes (Solved).
Source: Intuit Community forum.

I need Quickbooks pro 2019 for Mac but accidentally purchased the PC version. How do I change this?: 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 PC version
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for PC version [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: