first off, it isnt actually a pc ubt issue since it concerns more on unsettled arrears from your isp
anyway i can't seem to find a good board for it that's why i answered from here.
i cant exactly say it's a bluff since you are on a contract (i suppose) and the other party (your isp) may have enough grounds to pose legal actions against you if the contract was not fulfilled, breached or whatnot.
but from my experience and the least of what ive heard, there is a slim chance that the court proceedings are not being conducted as opposed to what was pointed out on verbal and written notices. technically, you waived your right to appeal if these notices (verbal/court summons) are deliberately ignored.
but why these proceedings aren't being fulfilled at most? i dont know why but if you are going to ask me from my pov, it all boils down to "quota"
if you have any idea of how their collections treatment works, or if you are not aware of that term (collections treatment)
then you may fall into their "bluff" and find your self paying your unsettled arrears for fear of paying it behind bars.
collections treatment is a process where a firm (your isp) pass on its obligation on "collecting" unsettled arrears to (mostly) third party offices (not entirely a part of the said firm) so that they persistently reach on you in different forms (verbal/written) to urge you on paying your long overdue debt. it usually lasts for 6 months and you are being elevated if nothing was heard from you. if you reached to the point where in you are issued a court summons, prepare yourself to an "atty call" because that would be the longest day that you know of.
if they let it go past 6 months (customers dont usually have tracks on the first time they were contacted by these collections agency), you're good. that would only mean that you're within their threshold so they can allow more debts to be written off or there are more to be prioritized (customers with higher amounts of debts). but if luck is not in your side, you will be their final card so they can meet their quota or else, they lose their agency tie up with your isp.
either ways really sounds a pain in the a$$ but that's that. they are just doing their job and it so happens that their job is collecting from you.