Holding deposit confusion

[Ana James]

I applied for an one BR apartment at a community in CA. The leasing manager was able  to convince me to deposit the holding deposit check the same day even before filling my application form. I submitted the check after their office hours and she made me sign a  holding deposit form which says I will be responsible to pay prorated rent for the time period they hold the apartment for me (max of 2 weeks, March 26th).

My application was approved the next day but there were conflicts regarding some of the advertised amenties ( microwave and clubhouse) which they decided to dishonor saying the condition is as it was shown. I still decided to move in.

They cashed in the check the same day. A week later, I had some issues with the move in date and requested them to move it forward by another week. They said to consider my request, they would need  extra 2 days and if they don't extend, I will be charged for those days as well else I could cancel same day and pay prorated rent for 9 days. There was confusion regarding number of days ( they were charging me for both day I deposited the check( after hours) and current day. This amount was $80 more than the holding deposit so felt like a big hit.

I couldn't afford to pay extra rent so I asked them to cancel over email in case they can't look into my request. One day later, my present landlord agreed for me to vacate earlier and I sent a mail if they would allow me to move in on March 25th. ( day earlier than my original move in date on the holding deposit receipt). They are saying your request is cancelled and you owe us $80.

Now I'm concerned about the legality of the document and if I'm obligated to pay more than the deposit in this condition when I eventually agreed to move in on the decided move in date.

I'm ok paying them to avoid the situation of them reporting me to any Credit bureaus for $80 but I'm curious about the legality of the document. Let me know your views.