First, I don't know where the timeshare company is located -- but, if it's located outside of the USA, then the consumer protection and bankruptcy laws that typically protect U.S. persons don't apply to your timeshare. This may answer your question.
Assuming that the timeshare company is located in the USA, then there is a "split of authority" from different bankruptcy courts in the USA concerning whether or not the reporting of a delinquency to a credit reporting agency violates the Bankr. Code 362(a) automatic stay. Consequently, the timeshare company may simply be intent on risking a contempt citation by the bankruptcy court -- which the debtor may be unwilling to pursue due to the additional litigation costs which may be involved. Or, the timeshare company may simply be ignorant of the law -- that's something I can't evaluate -- but, if I were representing you, I would send a letter to the timeshare threatening a contempt action unless it immediately removes the negative credit reports. That's usually enough to resolve this sort of problem.
As for why the timeshare is refusing payment, it could be due to the timeshare believing that if it accepts payment it may be accepting a "preference" transfer, which it would later be required to return to the bankruptcy trustee. Co-debtors are equally covered by the automatic stay when one co-debtor has filed Chapter 13. Bankr. Code 1301(a).
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