Asshole-ish and Stupid Customers at your job

I work in A/P but because no one actually uses our automated telephone system, I get mostly A/R calls. One lady a week or so ago called in asking for a refund. I told her I didn't have access to that portion of the system, and that I'd have to transfer her to A/R. She told me no, I had to listen to her. I listened, and then told her no, I couldn't help her, but I could transfer her. She said she'd been trying to get a refund for the last several weeks and no one was calling her back, so she's done. I asked for her number so someone could contact her. She said "No! From now on you guys have to track me down! *click*"

I laughed. Right, big corporation going to waste its time tracking down someone to pay them 15 dollars. Hah!

Another lady called wanting to know about some invoices we owed her. I looked them up. We didn't have them. I asked her to fax them over. She said she already did and wasn't doing it again. I apologized that we didn't have them and explained we really couldn't pay without the invoices. She demands to know what we did with them. I ask her who she faxed them to. She gives me the name of a person who quit working there last October. I explained this to her, and asked her to fax them again. She said no, she demands to speak to my boss. I explain that he isn't in. She insists. I transfer her to his voicemail. She calls back and demands to speak to the CFO regarding my rude behavior. I explain to her that I'm trying to help her, but there's nothing I can do without the invoices. She insists. I transfer her. CFO never answers his office phone. That's the funny part. She hasn't called back either.

Jam it back in, in the dark.