<prompt> Human: So a few months back, my sister asked me to be her guarantor. I agreed. When I logged into the portal to sign the contract, I noticed she had also added me as the guarantor for one of her random ass friends she wanted to room with. After explaining to her how incredibly fucking stupid and unacceptable that was, I emphatically refused to sign her friends contract. Later, the apartments called me about the missing signature and I explained the situation and again refused to sign. Fast forward to a few weeks ago, I get a bill in the mail from a debt collection agency. This is where I fucked up: I assumed Id never hear from the other girl again, so I thought my sister was behind on her rent. She showed me proof that she wasnt so I figured they had sent this earlier, but that my sister had since paid. Turns out the girl was being charged for a no show on her contract and they are treating me as the guarantor. Neither the debt collection agency nor the apartments can show me documentation proving that anything was signed by me. But the debt collectors want an email from the apartments to clear me from the account. The apartments swear up and down that I signed, but somehow cant provide me with any proof.According to the debt collector, its been over 30 days, so if they dont get an email from the apartments within 48 hours, itll affect my credit. I have zero expectation that the girl would pay it even if I could get in touch with her.What can I do? How can I put pressure on the apartments to send that email?  <response>: Tell them to produce the signed document, and refute with your communications about how you will not sign. 