I'm in a pickle in Los Angeles, California.
In December of 2006 my partner and I allowed his friend and her sister to come and stay in our extra bedroom with a verbal agreement that they would be there for one month. As it was for a short time only, and since we were doing a favor for people we thought we knew pretty well, we did not add them to the lease; the landlord was not aware of and did not approve their move-in. At the time I didn't know what a big no-no that is. We now know how stupid that was.
Four and a half months later, they still had not left. They are paying an agreed-upon share of rent to us (though often it is late). At the beginning of May we were so fed up with their behavior, which had deteriorated significantly over the months as they got comfortable and began to show their true disregard for us and our property, that we sat them down and had them sign a written agreement that laid out the terms for the remainder of their stay, including an end date of June 15th. Tomorrow.
Today they told us they "are going to stay for two more weeks." What can we do? They are now claiming that they did not understand the terms of the written and signed contract. The language of the relevant passage is as follows:
"The agreed-upon end date of your stay will be June 15, the date most recently discussed. We'd be happy to prorate the rent so that the portion of June you're stayin is paid at the beginning of the month as usual, or to move to weekly payment during June."
Am I wrong in thinking that this language clearly states that they are to leave by the 15th, and that "the portion of June you're staying" clearly means those first 15 days, and does not, as they are now claiming they thought, mean that they can at will decide to extend their stay to the end of the month? This was discussed in detail with them, we asked for their input and to suggest edits to any of the points that they wanted to change, and everyone signed the agreement on May 4th.
So... do we have any legal recourse to make them leave since they are not on the lease but do have a signed (but unauthorized by the landlord) sublease agreement with us?
I am aware that it was a very bad idea to enter into this arrangement in the first place. At this point I just want to know how (and when) I'll have my home back. My partner and I are at the point of trying to schedule our days so that we never leave them alone in the apartment. These two have access to everything we own, and they have shown an astounding lack of personal integrity in a number of ways recently. I don't trust them and I want this nightmare to be over.

