Kelly Benefits Payroll

This is a complaint against Kelly and Associates (1 Kelly Way, Sparks, MD 21152). I had insurance with them through Kelly. Got Medicare 7/1/22. Advised them of the change of insurance starting May 2022. See supporting documents.
Despite the continued correspondence, via phone calls and e-mails, with Mr. [name], informing them of my plan to discontinue coverage, Kelly and As. continued to send bills for subsequent months up to $3,028.74, even though Ms. [name] (my office manager), had continue to contact Mr. [name] to reiterate that I did not need coverage because of the switch to Medicare Part B.
Bills stopped coming for a while, leading me to believe that the companies realized there was no money due to them. I was very surprised when I received notice from a collection agency, stating that I had an unpaid bill. They never warned me that the bill was going to collections. I’m not sure what happened but my impression is that there was lack of communication between Mr. [name], Kelly and Associates and the insurance company.
Since 2011, I have paid Kelly and Associates approximately $117,470.72. I’m very healthy and do not take any medications. While being covered by them, they spent less $5,000 on me.
In addition, I don’t understand what they are billing me for. By July 1st, 2022, I was covered by Medicare and it became my primary insurance, so I don't know what service they were providing, certainly not healthcare insurance. Had I needed medical attention on or after July 1st, Medicare would have paid for the expenses. I emailed Medicare regarding this issue.
Attached documents (no room)
email 05 31 22 to K [name]
email 05 31 22 to K [name](2)
email 06 29 22 to [name]
email 07 13 22 to K [name]
email 01 18 23 to K [name]. No answer yet
collection letter
ins card