Parents I-485 rejected due to incorrect fee post I-94 expiry

[pdoshi]

We have an approved I-130 for my mother but her 485 got rejected due to incorrect fee. We received this rejection after her I-94 expired ( approximately 10 days ago). The documents were returned with a stamp on them and a rejection notice. Anyone have experience with a similar case and way forward ? Can I just refile with existing stamped documents and pay the correct fee or do I need to file new documents? What will be her current status ? Should I file an I-94 extension as backup

[newacct]

Your parents are in the Immediate Relative category (spouse, parent, or unmarried under-21 child of US citizen). People in this category do not have to be in status to be eligible for Adjustment of Status. Even if their I-94 had expired for years, they can still file I-485. It is not only unnecessary for them to apply for extension of stay (being a waste of money and time), applying for extension of visitor status would also require then to lie about their plans to leave. They should definitely NOT apply for extension of stay. They can re-file I-485 at any time if they need to, before or after their I-94 expires. As to whether they can send back the documents or have to file new documents, I don't know.