This is really not a family law question. I would consult with someone who has transitioned their practice to include Affordable Care Act issues. As a note, under the Affordable Care Act, a child may obtain coverage up to 26 years of age, but it is not required. Unless there is an Order that requires coverage, there may be little that you can do to obtain the health insurance card. I would suggest trying to contact the company directly and asking for a duplicate card, if they will not provide the card, I think your options are limited. As for the Social Security issue, I would contact an attorney who handles that type of matter and consider options.
Your mother is not required to provide you with health insurance. If you know the name of the company, you can try getting your own card, but otherwise you need to get your own coverage. As to social security, the only money that came in were dependent funds meant to replace child support. This was not a large amount of money and was intended to be used to pay for your housing, food, clothing, and other regular expenses. Thus it was entirely appropriate for your mother to have taken this money and spent it toward the household. As to income taxes, you are entitled to file on your own and claim yourself. She can only claim you if she has provided for you financially. If she claimed you anyway, unless that somehow impacted your tax filing, you have a "no harm, no foul" issue.
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