Is there anyone clueful at Conxion ?

Or, who do you contact in Conxion to stop receiving their notification

My employer seems to have gotten onto their list by mistake (no current or
former connection to Conxion) and since September, no-one in Conxion has
deigned to reply to requests to cease and desist via appropriate channels
(ie, the return email address, phone, domain/IP/ASN contacts).