866-204-7902

Asking me to file tax return which we have already file long time ago.That paper has our name spell wrong and 866 204 7902 phone number is listed on that paper.

I received a letter from " State of California Filing Enforcement Section MS F180 FRANCHISE TAX BOARD  PO Box 942840 Sacramento CA 924240-0040       Telephone: 866.204.7902      Fax: 916.855.5646  ftb.ca.gov/inc "    That paper said " We believe you need to file a 2015 California income tax return."  I went to www.ftb.ca.gov checked the right FTB board information " Website . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ftb.ca.gov
Automated Telephone Service
FTB’s automated telephone system provides services in both English and Spanish to callers with touch-tone
telephones. Callers may listen to recorded answers to frequently asked questions about state income
taxes, 24 hours a day, seven days a week. Callers may order personal income tax forms, verify the status
of their personal income tax refund, check their balance due, and confirm recent payment amounts and
dates, 24 hours a day, except 9:45 p.m. Sunday to 12:15 a.m. Monday. Callers may order business entity
tax forms 6 a.m. to 10 p.m. weekdays, 6 a.m. to 4:30 p.m. Saturdays.
From within the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800.338.0505
From outside the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.845.6500
General Telephone Service (Taxpayer Services Center)
Telephone assistance is available year-round from 7 a.m. to 5 p.m. weekdays, except state holidays. We
may modify these hours without notice to meet operational needs.
From within the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800.852.5711
From outside the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.845.6500
Tax Assistance for Persons with Hearing or Speech Impairments
Persons with hearing or speech impairments:
TTY/TDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800.822.6268
Tax Practitioner Services
✓ Hotline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.845.7057
✓ Hotline (fax) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.845.9300
✓ e-file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916.845.0353

You should go down to your local California Franchise Tax Office and show them a copy of the letter to make sure it is authentic.  At that point (if the letter is valid)  you can request a Form 540 with any other forms necessary to file whatever taxes are due.  You'll need a copy of your Federal Form 1040 (for that year) in order to do this.

If you have a lot of complex income from various sources, you'll probably need the services of an Enrolled Agent or CPA.

I got a letter saying they believe I need to file a 2016 California income tax return. I have filed years ago and have spent their refund years ago. The number they have listed 866 204-7902

Whose number is this real

Well, I would suggest that you learn to read.  Once you can do that you will find out that there is valuable information on what you should be doing. Of course you can remain clueless by not learning to read and learn but that is no way to enter and remain for the rest of your life.