Apria healthcare Global Receivables Solutions inc. falsely sent my name to collections plainview ny

My husband has a very bad heart condition and We have been dealing with  Apria healthcares billing mistakes for years My husband David has spent hours on the phone dealing with there mistakes!explaining  over and over to  customer service  how we were told by you that we are 100% covered by our insurance for his medical supplies. Sleep apneasupplies. Like tubes and masks that he needs for his sleep apnea. 
 

He always gets the same thing being put on hold, them coming back on the phone after 10 minutes or so and then he is told o yes you are correct, you are fully covered there should be NO CHARGES!
 
Now he receives a letter from Global Receivables solutions,inc  debt collector stating  stating that he owes $467.76. 
He Then contacts Apria healthcare again telling them about this notice and he is told yes they see he was fully covered but there is nothing they can do about this now its out of there hands.. This needs to be cleared up and cleared up once and for all! My poor husband has spent hours of frustration, anxiety,and wasted valuable time on Apria healthcare's incompetence. They need to make things right.  
   Thank you,