You should file a Motion with the Court to have your ex wife cited for contempt. You will need to file an affidavit setting forth the circumstances of her failure to follow the Court's order. Your ex will be served with the documents by a process server and ordered to appear in Court and show cause why she should not be committed to prison for failing to comply with the Court's order. You can also obtain an award of attorney fees against her if you succeed. The other option is to file a Motion requesting that the Court enter a judgement for her share and then garnish her wages or bank account to recover any amounts you have had to pay to prevent forclosure.
Your father should at least be paying reasonable rent which could be used towards the mortgage.
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