“ With respect to credit card which may be used for extensions of credit in sales transactions in which the seller is a person other than the card issuer, the card issuer may not, by contract or otherwise, prohibit any such seller from offering a discount to a cardholder to induce the cardholder to pay by cash, check, or similar means rather than use a credit card. ”

“ In the case of a billing error where the obligor alleges that the creditor ́s billing statement reflects goods not delivered to the obligor or his designee in accordance with the agreement made at the time of the transaction, a creditor may not construe such amount to be correctly shown unless he determines that such goods were actually delivered, mailed, or otherwise sent to the obligor and provides the obligor with a statement of such determination. ”

“ If an open end consumer credit plan provides a time period within which an obligor may repay any portion of the credit extended without incurring an additional finance charge, such additional finance charge may not be imposed with respect to such portion of the credit extended for the billing cycle of which such period is a part unless a statement which includes the amount upon which the finance charge for that period is based was mailed at least fourteen days prior to the date specified in the statement by which payment must be made in order to avoid imposition of that finance charge. ”