Leave without Pay

I want to go on early leave sa work. (7months) company allow it pero need ko magsubmit ng medcert or recomendation letter. problem is ayaw ni ob ako bigyan ng medcert or recomendation letter. Hindi po ba tlga nagbbgay kaht sinong OB ng ganun for leave. reason for leave: hirap sa byahe(commuter maximum 2hrs byahe. 4hrs balikan )hirap sa work.