Council tax arrears paid, but Dukes baillif chasing fees

Reliablebuddy

Hi,
I'm hoping to get a good advise to make a decision on this matter.
I had a £100 council tax arrears which I settled online a couple months after I moved from a property where I was a private tenant.
A month or so before I settled the account I had received a letter from Dukes baillif to my partner apartment. 
I called the council and they confirmed my account is cleared on their end.
I and my partner are no longer together, I've moved home and made the council aware of my new address.
6 months later, the baillif  has gone to my ex partner threatening to cease anything in her house to recover £310. Which seems to be their fees.
My ex told them I no longer live at this address. As per their request to prove that a council tenancy agreement was emailed to Dukes as she lives in a council flat.
Yesterday some from Dukes sent a letter said" delivered  by hand" with no breakdown of the amount due:
My questions is:
Am I obliged to pay?
Can they take me to court? 
Will I have a CCJ on my credit file?
Where will they send the court order as they don't know my address?
What would you do in this situation?
Looking forward to hearing your wise advise.

Many thanks

lincroft1710

It seems, from what you have said, that Dukes were instructed by the council before you settled the arrears. Therefore you may owe Dukes money for their fees. I have no idea if £310 is fair and reasonable. They can take you to court and if they win their case and you do not pay, then you could have a CCJ.

If a current address is not known, correspondence is sent to the last known address.