For a creditor to be paid in a chapter 7 or chapter 13 bankruptcy case, it is required to file a proof-of-claim form. Just as the name implies, the creditor must provide evidence of the nature and amount it claims it is owed.
Any party in interest can object to the claim and there is not deadline of the objeciton date in the Bankrutpcy Code. The objection must be in writing and noticed served on the claimant with thirty days notice of the hearing to consider the objection. A "party in interest" is anyone that is financially impacted by the claim, which rarely includes the bankruptcy debtor in a chapter 7 case.