Yes and this is why: Although you were below the age of Adulthood (Age of Majority), if the medical services were necessary you can be held responsible for them. This also applies to other necessities like rent for housing.
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In general, a guarantor's role is to guarantee repayment in the event the primary obligor defaults. By having a guarantor, it does not relieve the primary obligor of his or her liability on the account. Depending on the age of the account(s), you may either want to dispute them, settle them, or leave them be. Speak with a debt relief and/or credit repair attorney in your state for further assistance.
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