If the dean is unable to help, find out if your diocese has an office of mediation. The purpose of this office is to assist the faithful in finding agreeable solutions to disputes. The dean can direct you to the office of mediation, if one is available. If the office of mediation is unable to assist you in obtaining an agreeable solution, or if your diocese does not have an office of mediation, approach the bishop or one of his vicars according to diocesan protocol. In larger dioceses, particularly those with an archbishop, it is proper to approach a vicar before approaching the bishop.
All dioceses have a vicar general.
The larger dioceses also have episcopal vicars, who are often bishops. These vicars have direct authority over the priests entrusted to their care. After approaching the vicar, seek the assistance of the bishop himself. If the bishop is unable to help, contact the archbishop of your ecclesiastical province once. N.W., Washington, DC 20008.