Perlindungan hukum terhadap pihak kreditur bank selaku pemegang hak tanggungan atas agunan sertipikat hak guna bangunan (HGB) yang jatuh tempo (studi kasus pada PT Bank XYZ berkedudukan di Jakarta) = Legal protection against creditor bank as the top holder of collateral mortgage broking certificate (HGB) maturity case study at PT Bank XYZ is located in Jakarta