If an insurance company is engaging in less than good-faith negotiations, or has extended an unreasonably low offer, the only thing that you can do is take your financial recovery out of their hands altogether by filing a lawsuit in the appropriate jurisdiction. You will almost certainly require the skills and services of an experienced personal injury attorney to accomplish this. There is frankly and realistically nothing else that you can do to bend an insurance company to your will and force them to do something they're not otherwise willing to do.
The nation's major property and casualty insurance companies are massive and enormous entities the generate astronomical revenues and astronomical profits.
Paying a few hundred, a few thousand, or even a few hundred thousand additional dollars on a single claim ultimately simply would not and does not matter to an insurance company.
The corporate mentality of an insurance company is not to care one way or the other about an individual claim or hundreds or perhaps thousands of individual claims. Their business model is to collect premiums, invest them wisely, and reap the profits. Control of claim expenditures is a far less significant consideration.
The only way to combat the insurance company is to take the decision and determination of what fair compensation for your personal injury is off the table and completely out of their control. It is only proceeding with litigation and allowing a judge or a jury, as appropriate, to determine what fair compensation you should receive that I’ve found to be a tried-and-true, consistently effective, mechanism.
That's not to say that a well-thought-out articulate intelligent presentation of damages might not sway a given claims adjuster on the merits of a particular case. However, at the end of the day, they're only going to be swayed if they want to be swayed, and if the amount about which they're influenced fits within company parameters. Additionally, a pertinent complaint filed with the Maryland Insurance Administration may prompt an insurance company to take action in a timely fashion, but it will not compel them to disregard corporate strategies and business considerations in any particular case or in any specific case.