State tax filing

I asked my question more in full here: 

 

https://ttlc.intuit.com/community/state-taxes/discussion/why-did-i-get-a-request-for-tax-return-cali...

 

But this topic intrigued me because CA is causing issues for me with a letter saying I need to file taxes in CA even though I live and work in GA.  And the majority of our income was from non CA sources. Probably less than 30% came from CA client. The rest were other states including our home state of GA. 

 

According to their form, if my  hubby and I jointly made over 34K I'm required to file in CA even though we don't live there. And I haven't been in that state or been a part year resident since 2015 when we moved but the TY in question is 2017. Any advice? If I fill out the form as they ask for b/c that line item is above 34K they want me to go through the process of filling out CA taxes just because it's over 34k!! Who does that? I had clients in 5 states that TY. And I certainly wasn't about to file state taxes in all 5???? Is that just a CA thing? How do I get out of filing taxes (which means buying software, filling out taxes for it, then filing the taxes all by 8/7? I just got the letter about this TODAY. So that's 1 month. But I don't see why it's any of their business what we made for the year in full when I don't live there?  We already paid taxes for that year in full to federal and GA. 

 

They do not provide a phone number to call and ask questions in this letter from CA.