If an employee whose minimum rate of wages has been fixed under this Act by the day works on any day on which he was employed for a period less than the requisite number of hours constituting a normal working day, he shall, save as otherwise hereinafter provided, be entitled to receive wages in respect of work done by him on that day as if he had worked for a full normal working day:

Provided, however, that he shall not be entitled to receive wages for a full normal working day--

(i) in any case where his failure to work is caused by his unwillingness to work and not by the omission of the employer to provide him with work, and

(ii) in such other cases and circumstances as may be prescribed.