INVOICES NOT SENT TO CHRONIC PAID FROM SAVINGS!!!!

My Grandpa suffers from COPD - his oxygen has been approved on chronic (after battling with Vital Aire to get that right!) we have since received a statement stating that we owe under 2k to you guys!! called discovery and they mention that this is because VITAL AIRE DID NOT send it through under chronic! Today (07/08/2015) they say that the invoice for MAY 2015 will be resent - WHY HAS IT TAKEN SO LONG FOR THEM TO CLICK THAT IT DID NOT GO THROUGH CHRONIC - WHY DO WE NEED TO FIGHT WITH *********** PEOPLE FOR 15 MINUTES IF NOT LONGER ABOUT THIS! NEEDLESS TO SAY THAT THEY NEVER RESPOND TO YOUR EMAILS EITHER! I WANT THIS SORTED OUT YESTERDAY!!! SO FRUSTRATED WITH THEM!!!!!