Nashua Mobile Account overdue

I received sms from NBA stating: No payments received. Payment required within 24 hrs on your NBA Nashua Mobile acc. Call ***. ***. I contacted the call centre to find out what the issue is, and was told it was an account handed over for collection from Nashua Mobile. I explained that I have been sequestrated in 2008 and that the account was supposed to be part of the claims against my estate, and that I have been rehabilitated in 2012. Their response was that I should pay the outstanding amount as I am now rehabilitated and still liable for the outstanding amount. As far as I am aware all claims before my sequestration are now null and void as a sequestration cancelled all claims against me. I am now being threatened they will blacklist me.