Definition of "non-payment"

[...] it appeared that in 1909 the Excess Insurance Company bought the right to recover certain sums of money due from the light railway company, and, on non-payment, secured the appointment of a Receiver in respect of the undertaking and assets of the company.

1944 March and April, “Notes and News: Weston, Cleveland & Portishead Light Ry.”, in Railway Magazine, page 116