The bank reduced my Home Equity Line of Credit (HELOC) before they contacted me. Does the law require them to notify me before they reduce the credit line?

No, advance notice is not required. If the creditor is permitted to reduce or "freeze" a HELOC, it must provide written notice within three business days of taking the action. The notice must provide the specific reason(s) for the action. Also, if the bank requires the customer to request reinstatement of the original credit line because of changed circumstances, then the notice also must provide instructions on how to request reinstatement of credit privileges.