Very unhappy of my treatment by this company. If I...

Very unhappy of my treatment by this company. If I could rate them lower I would! 1 week ago I received a bill from a collection agency, I had never received a bill or notification of any issue. I gave them the information needed and now I have received another collection agency letter on another charge that I was never notified of?
This must be there normal practice, what a waste of money! I have used them for many years. I will now look for another group to have my imaging done.