Can I write a cheque using a credit memo and a sales invoice at the same time? If so, how??

Hello tami@redbarnhay.

Thanks for reaching out to the Community for support. Id be happy to help.

Making sure you're recording your transactions correctly in QuickBooks is an important part in maintaining clean books. I recommend reviewing this article for steps on how to proceed with refunding a deposit. 

If you have any other questions, feel free to reach back out here.