We have a work comp forum here also, there might be past posts on a topic like this..
Another thought is use the whole site search for work comp, meds, and any other keywords that might find related topics..
Many other health conditions here might have similar w/ comp issues..

Seems like the Drs office and your atty need to have a talk..
He should be able to write a letter to Drs office, stating something to the effect of how important for your health & regulations by W/C for things to be done timely.. a legal & official notice of care letter..

And if both of those let you down- call or write your gov officials, and whoever owns or the oversees company of the drs office.. over & above the dr & the office manager..
Of course they may retaliate by not treating you anymore, so that is a consideration before it goes that far.. are they good other wise or not so good..or the best dr option locally..