First and foremost, you need to be certain that your claim is not barred by the statute of limitations. The statute of limitations is the time within which you must bring your claim or else forever be barred. Each state sets the statute of limitations for claims arising within the state. You should consult with an attorney immediately to determine the statute of limitations within your state as the statute of limitations for personal injury claims in many states is as little as 1 or 2 years.
If your insurance company refuses to pay for treatment that you believe is related to your motor vehicle accident then you likely have the right to have their denial of coverage reviewed and decided by an independent third party. You may have the right to file a law suit against the insurance company in your local court system. However, most insurance policies are binding contracts and often require arbitration to decide disputes regarding coverage. Arbitration is a cost effecitive method for resolving your claim. An independent arbitrator will listen to both sides of the case and make a determination as to whether your claims are covered. Be aware though that arbitration is not always binding and may be appealled to trial within the court system. To begin the process you simply need to make a demand upon your insurance company to arbitrate the matter.
Aside from your medical bills, you may also be entitled to receive compensation for pain and suffering related to your injuries. Even though you were hit by an uninsured driver, uninsured motorist coverage under your policy likely includes coverage for both your economic damages (i.e. medical bills) and your non-economic damages (i.e. pain and suffering). An attorney can help you assess this better.
You may also be entitled to recover attorney fees should your state have a statute that entitles prevailing claimants to attorney fees when insurance coverage is wrongfully denied.
As I am licensed in Florida and Vermont, I cannot offer you specific legal advice as to Maryland state law. However, generally, I would respectfully recommend that you contact a personal injury attorney in your area and see whether or not the attorney is willing to undertake your representation. Do not delay in speaking with a personal injury attorney, as the statute of limitations may be fast approaching and you may not be aware of it. A Maryland attorney can advise you as to the state statute of limitations.
Unfortunately, the gap in treatment which you describe is the very type of thing which an insurance carrier looks for and uses as an excuse to deny payment for any treatment received after a significant gap. This type of situation is covered in one of the Legal Guides which I have published on Avvo.com. You may wish to review that Guide as well as some of the others I have published, which deal with many of the issues you are currently attempting to contend with.
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