Made a purchase through an online payment service. I had to close the bank account before they collected. I contacted them and let them know what was going on and they said that they would give me instructions on how to pay. Well today I get a call from a guy saying he is in the fraud department and that if I don't pay today or give them a new account number he is going to file a report that will freeze all my bank accounts and report it as fraud to the authorities. I am willing to pay but don't have the money today. The company is in canada. Can they do what he says. Please HELP if you can!

They can't freeze your account without a judgment, period. You should, though, get the alternative payment method instructions and pay them as quickly as you can or return what you purchased.

Bill collects lie, first rule, if what they tell you is not in writing, it is a lie.
Even if they tell the truth, they can change it if not in writing.

If they wish to charge you with fruad, they can contact the police and file charges, ( that they could do most likely)

As for as freezing your bank accounts, they don't know them first, next they have to go to court and get a judgement first.

I would arrange to send them a money order for what you can today. And then make regular payments for this.

If you pay by check or (God forbid) give them routing and check numbers over the phone, they can merely try to collect more money from those accounts.