You can reach out to our helpline within the QuickBooks product. For QuickBooks Online (QBO), Select Help then click Contact us while for Desktop you can check the steps here.
Regarding the list of customer that you want to print, you can create a report to do this. Here's how:
On QuickBooks Desktop, go to Reports menu at the top. Then select List. You can choose from Customer Phone List or the Customer Contact List report. You can customize the report to remove or add columns. Then print the report by clicking the Print button.
On the other hand, if you are using QBO, you can run the Customer Contact List report then click the print icon.