Cancel and remove payment from the online web turbotax?

If you have not paid and submitted your tax return you can quit  and chose to start over. If you are using any of the additional schedules you cannot use the free version of the program.

https://ttlc.intuit.com/community/taxes/discussion/how-do-i-start-over-i-had-to-quit-and-when-i-came-back-to-start-again-it-will-not-let-me-go-to-where/00/753729

 check this website(different from the turbotax site) to see if you qualify for a free file.

https://freefile.intuit.com/