25. A mortgagee shall not exercise the power of sale conferred by this Act unless —
(a)
notice requiring payment of the mortgage money has been served on the mortgagor or one of several mortgagors, and default has been made in payment of the mortgage money or part thereof for 3 months after the service;
(b)
some interest under the mortgage is in arrears and unpaid for one month after becoming due; or
(c)
there has been a breach of some provision contained in the mortgage deed or in this Act, and on the part of the mortgagor, or of some person concurring in making the mortgage, to be observed or performed, other than and besides a covenant for payment of the mortgage money or interest thereon.