My question involves landlord-tenant law in the State of: California

Hi,

I just recently sub-leased an apartment from students for two and a half months. The renting was not official, as we payed them and they payed the landlord.
The first month, we moved our stuff in on the 16th while they were still living there, had the keys, etc. We received our keys on the 25th and lived in the apartment for 5 days. What they were doing there from the 16th-25th we do not know. In the end, they charged us half a months rent, and the month's electricity. We were okay with this until something later on happened.

The next 2 months, we lived there full, so we are okay with bills on those months.

The following month, we moved out on the 4th, and they came to take the keys (they were not moving back in for 2 more weeks so the place is basically empty). They want to charge us for 4 days rent.

I was wondering if this is fair? We don't have anything written, only emails, texts, and a letter that she mailed me that says "..here are the keys.." Because she mailed the keys to us.

We were never told we would be charged 4 days, if this was the case we would have moved out 4 days ago. If they do do this, can we argue that the first month we were there, we did not even receive keys until the last 5 days of the month, there should be no reason we are charged full for their electricity and half the rent.

They have a $400 deposit from us.

Thanks,
H