Not sure what you mean.   Do you mean you were just using the software to enter some amounts to get an estimate?   Sure hope you did not do that in the same account you used to prepare your actual tax return.   And why would you need to "cancel" printing?   Did you go all the way to the file section and choose print to mail?   

Do you mean the quarterly estimated payment slips?  Those are optional.  You can shred them.  Don't know if you can not print them.  But if you print from the pdf you can select what pages to print.  

If you just want to not print the vouchers, you can tell the printer to skip those pages of your pdf printout.