Zoning not accurate?

[Marc Dufour]

I bought a land at a tax deed auction in northern California. I verified the zoning by looking online at the zoning on the city page (they have a lookup map for each APN) and it says residential. I also went to the city zoning department and the clerk verified, looking at the same online database, and confirmed it is residential. This online database do have a disclaimer though that the data may not be accurate, updated, etc...this is why I went to the city to check in person.

After the tax deed sale happened and I sent the money, I had 2 different realtors who called the city zoning, and the zoning person (different clerk or someone above, I am not sure) mentioned it is an open space that cannot be built. I am getting really anxious...what next steps do you suggest? Any legal action?