what should i do?

It's a scam - no one is going to arrest you.  Never pay for any debt which is not proven to be yours - legitimate debt collectors are legally bound to send you a debt validation letter showing original creditor, amount owed, date incurred and whether they are legally entitled to collect said debt in your state.  If someone calls and threatens you with arrest or garnishment of wages they are in violation of the FDCPA.  Report the calls to the FTC, the FBI and your state's Attorney General.  You may also wish to place fraud alerts with your banking institute and also with the big three credit agencies - Experian, Equifax and TransUnion.

If the callers will not send a debt validation letter via MAIL (not email or fax), proving you owe the debt to them, they are scammers.  Report them to the FTC, the FBI and your state's Attorney General.  Let them know that you've reported them.  They will probably keep calling - that's how they scare people into paying for debts they don't even owe.  Ignore the calls or block them.  Remember - if a debt collector will not prove you owe the debt then they are trying to scam you.

SCARE TACTIC MY DEAR...DONT WORRY ABOUT IT DONT LET THEM KNOW THAT THEY ARE UPSETTING YOU BECAUSE THEN THE PHONE CALLS WILL NEVER STOP

They called me also it was very hard to understand.  Talked about a lawsuit was being filed.  I told them go ahead asked did I have an attorney.  Said yes wanted his name and number.  They called me 20 times within 10 minutes I kept hanging up they kept calling.  I finally beat the phone on the table real hard and they finally stopped calling.  Told me I had committed fraud with my pension and I was going to be sued.  I told him do whatever stop calling me.  I don't care.