medical insurance credentialing

I am looking for assistance with medical insurance credentialing for my physicians. Specifically, I need help with provider enrollment. I am one provider needing credentialing under a group practice. I am licensed in all states wanting to enroll in major companies in all states and DC including medicare. so it's about 5-6 applications per state. It is all remote medicine so I'm not sure if every state needs an application or only the state that I reside/provide services from. I need a flat rate, and someone who is professional and experienced in the matter. per application rates won't be considered. Budget is around 750-1300