The trailer mortgage is a secured loan and is not discharged in bankruptcy. And, if your daughter continued to pay the note after bankruptcy, then she affirmed the loan and still owes it -- had she not continued to pay, her obligation would have been discharged.
Your daughter can simply stop paying and the lender will repossess the vehicle and then get a deficiency judgment against your daughter. If she has no ability or assets with which to pay, the lender will be unable to collect.
Or, your daughter could file for bankruptcy against (after 6 years, from the last bankruptcy, minimum), and that would end the entire issue forever. Meanwhile, she can't really prevent the lender from calling for payment. If the lender sells the loan to a third-party collection agency, then your daughter can demand that the agency "cease and desist" from continuing to contact her concerning the debt. But, as long as it is the primary creditor who is calling, the only thing your daughter can do is say, "Hello -- goodbye."
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