As per the above conversation there to nothing to fear and he cant keep you in black list. Because he has not given the Appointment order to you,
But he gave you the check of half day salary which you have deposited.
Only one thing you need to specify whether you have a proof of attendance in your worked company.
And for your safe side it is better to send him a register post seeking the appointment letter since you have not received so far till your joining so that he will come to your end and request no need of resignation letter.
For any quire mail to
22nd February 2016 From India, Hyderabad