I don't owe CA a cent but they just won't stop calling me

I had a several payday loans a while back and paid them off. A few months ago, I was a victim of identity theft and all of a sudden I found tons of ACH's coming out of my account, I'd see money coming in and immediately coming back out and then I'd get stuck with the fees. Finally after arguing with my bank I closed my accounts. they claimed that since I had several payday loans before, how can they distinguish that I didn't take these new ones out too. They wouldnt' investigate the matter. Since closing my accounts, I have gotten dozens of calls at work from these payday loan companies, when I tell them I didnt' take out any loans with them, they claim they have my information and I'm responsible for the debt.
I have endured Ellis Crosby & associates, by getting one of their nasty threatening calls at work. I scared me to death and once I calmed down, I went online and found this site, needless to say, the next day when they called, I told them I knew who they were and that they were under suspension so I wouldn't pay them and never heard from them again.
I have gotten repeated calls from other companies too. QuikPayday who I had had a prior loan with is pulling the same thing, I told them I didn't take out another laon with them and they insist I did to the tune of $1200! They call me everyday, send me e-mails and won't quit. Cashnet is the same thing. I've sent these people cease and desist letters but that hasn't deterred them at all. As far as I can tell there appears to be 12 payday companies that insist I took loans out with them and I didn't, I don't owe these people a cent but they just won't stop. I'm at witts end and just don't know what to do.
I feel helpless!