A $20,000 promissory note has ballooned into a $1.4 million judgment against the debtor. A Cook County judge ruled that a 50 percent monthly compounded interest rate in the note is valid, finding that the loan wasn’t subject to caps allowed under state law. In May 2010, Texas-based doctor Parnel E. Desir gave $20,000 to Kenndol Desronvil of suburban South Holland. In a 2013 complaint, Desir alleged a breach of contract because Desronvil never repaid the note. The money was meant to fund Desronvil’s …