If you intended the $6500 contribution--made in January 2024 for the 2023 tax return--to be non-deductible for a future backdoor Roth conversion, then your 2023 form 8606 should show $6500 as your total basis on line 14. (Unless you had a prior basis on line 2 was more than zero, in which case the new basis on line 14 should be the old basis plus $6500.)
You need to start by preparing an amended form 8606 for 2023. HRB should do this for free if they screwed up. You should also check your 2023 return to see if you took a tax deduction (schedule 1 line 20) or they just entered the wrong total for the contribution (form 8606, line 1 and line 4 should both be $6500).
To file for 2024, you need the numbers from a corrected 2023 form 8606. You may be able to make the correction manually, so you don't have to wait for HRB to do the amended return.
