Most likely a debt scam call. One of their fave phrases is to state after cold calling you is "that there is a complaint" against you. Which is total nonsense. Debt collectors don't deal in complaints. They collect debts. Just the start of a process intended to scare money out of you. Ignore and block the calls.
Just because someone on the phone calling you says you owe a debt does not mean you actually owe it.
If a voice on the telephone claims you owe a debt:
1. Demand the person give you his or her name, company name, and address
2. Demand a debt validation letter by US mail. E-mail no good.
3. Do not pay the collection agent or anyone else a dime until the debt is validated
Of course they won’t do this, no scammer ever will, so simply ignore them and block their calls.
If they are bothering you, report them:
http://www.consumer.ftc.gov/articles/0149-debt-collection (Threatening civil proceedings with no intent to follow through, or threatening criminal process in order to collect a civil debt is a violation of the Federal Fair Debt Collection Practices Act.)
Also contact your local attorney general
If they continue to bother you, and you know you do not owe any money, tell them that you know this is a debt scam and that you are making a complaint to the police for extortion. Once you get a copy of the police report and they call you again , just read out the file number and the name of the PD or Sheriff’s office involved. Tell them you’ll be glad to send a copy to them at whatever address the jack***es are working out of now.
You'll probably have to yell at them and talk over them. Tell 'em no scammy debt collector is going to push you around.
You have to get tuff with these people because, being akin to thugs, brute force is (metaphorically speaking). the only thing they understand.