Worst debt collectors ever

For almost the past year I have been receiving sms's from OVAG, regarding an account to be settled. Being the person I am, never want to have debt, I took this serious, called them, waited ages for finally getting through asked for the invoice. They couldn't help/supply the invoice or tell me what I owe. Got the promise that it will be sent the next day...This repeated more than 15 times, with me spending more than 20hours on the phone to ask what I owe.<br> <br> Now they started to threat me with legal action. So mailing them doesn't work, also calling doesn't work. And I cannot get hold of any other options. <br> <br> So just a warning, I you want to get your money collected, they will not be able to help you, as want to pay, I just cannot get any help.