2 issues related to rent increase

[Stephen Homes]

I know this posting is for landlords and I am a landlord but now I am a tenant (a bit over 2 years) at California. Today (April 1) I learned that my rent was increased. Property Management claims that they have stuck a notice to my door 27 days ago plus mailed me the notice. I never got either notice. 

1. As a landlord I always send a certified mail to let the tenant know about any change (such as rent raise) to their lease. Does the same rule apply in California?

2. After 2 years the owner changed the property manager was changed to this one. Always my lease being renewed every 6 months. Prior to the 2 year the old manager verbally agreed to renewing for another 6 months but when the renewal day came he said the new management will give you the new lease. Now the new management claims that my lease is month to month. How can I defend myself in this situation?

Thank you