(a) Unless otherwise provided by the terms of the subscription, a subscription for shares of a corporation to be formed shall be irrevocable, except with the consent of all other subscribers or the corporation, for a period of three months from its date.

(b) A subscription, whether made before or after the formation of a corporation, shall not be enforceable unless in writing and signed by the subscriber.

(c) Unless otherwise provided by the terms of the subscription, subscriptions for shares, whether made before or after the formation of a corporation, shall be paid in full at such time, or in such installments and at such times, as shall be determined by the board. Any call made by the board for payment on subscriptions shall be uniform as to all shares of the same class or of the same series. If a receiver of the corporation has been appointed, all unpaid subscriptions shall be paid at such times and in such installments as such receiver or the court may direct.

(d) In the event of default in the payment of any installment or call when due, the corporation may proceed to collect the amount due in the same manner as any debt due the corporation or the board may declare a forfeiture of the subscriptions. The subscription agreement may prescribe other penalties, not amounting to forfeiture, for failure to pay installments or calls that may become due. No forfeiture of the subscription shall be declared as against any subscriber unless the amount due thereon shall remain unpaid for a period of thirty days after written demand has been made therefor. If mailed, such written demand shall be deemed to be made when deposited in the United States mail in a sealed envelope addressed to the subscriber at his last post office address known to the corporation, with postage thereon prepaid. Upon forfeiture of the subscription, if at least fifty percent of the subscription price has been paid, the shares subscribed for shall be offered for sale for cash or a binding obligation to pay cash at a price at least sufficient to pay the full balance owed by the delinquent subscriber plus the expenses incidental to such sale, and any excess of net proceeds realized over the amount owed on such shares shall be paid to the delinquent subscriber or to his legal representative. If no prospective purchaser offers a cash price or a binding obligation to pay cash sufficient to pay the full balance owed by the delinquent subscriber plus the expenses incidental to such sale, or if less than fifty percent of the subscription price has been paid, the shares subscribed for shall be cancelled and restored to the status of authorized but unissued shares and all previous payments thereon shall be forfeited to the corporation and transferred to surplus.

(e) Notwithstanding the provisions of paragraph (d) of this section, in the event of default in payment or other performance under the instrument evidencing a subscriber's binding obligation to pay a portion of the subscription price or perform services, the corporation may pursue such remedies as are provided in such instrument or a related agreement or under law.