I have unused RRSP contribution that I DO NOT want to use. TurboTax keeps putting it in my RRSP contribution amount. How do I NOT use it this year?

You can carry forward any RRSP Contributions or Unused Amounts to the following year as long as you have not "overcontributed" to your RRSPs or exceeded your RRSP Deduction Limit.

To do so using TurboTax Online, go to RRSPs > RRSPs Contributions to be Carried Forward > change the amount in the box "RRSP/PRPP contributions you are deducting for 2018" and the amount remaining will carry forward.