The holder of any retail installment contract or any installment loan contract shall not receive or collect any charges or expenses for collecting any delinquent payment, including, but not limited to, any service fees for accepting delinquent payments over the telephone or Internet, except as follows: The holder of a retail installment contract or installment loan contract, except a contract for the purchase of a commercial vehicle or an installment loan contract regulated by sections 36a-555 to 36a-573, inclusive, may collect a delinquency and collection charge for default in the payment of any such contract or installment of such contract, when such default has continued for a period of ten days, such charge not to exceed five per cent of the amount of the installments in default or the sum of ten dollars, whichever is the lesser. The holder of any retail installment contract or any installment loan contract for the purchase of a commercial vehicle, as defined in section 36a-770, except an installment loan contract regulated by sections 36a-555 to 36a-573, inclusive, may collect a delinquency and collection charge for default in the payment of any such contract or installment of such contract, when such default has continued for a period of ten days, such charge not to exceed five per cent of the amount of the installments in default. In addition to any such delinquency and collection charge, the retail installment contract or the installment loan contract may provide for the payment of attorney’s fees not exceeding fifteen per cent of the amount due and payable under such contract when such contract is referred to an attorney, who is not a salaried employee of the holder of the contract, for collection, plus the court costs. The restriction on charges under this section shall not apply to any expenses permitted under section 36a-785.