There is no requirement n the PADI certification to demonstrate four swimming strokes.
The PADI requirements for the "swimming" are:
"Swim 200 metres/yards (or 300 metres/yards in mask, fins and snorkel). There is no time limit for this, and you may use any swimming strokes you want." ~PADI
An instructor who says different is adding stuff to the course and that is not permitted:
"Any individual who can meet the performance requirements of the course qualifies for certification. " ~PADI
Contact PADI and file a complaint against the instructor. If you passed PADI requirements you are entitled to a certification. If you met PADI standards but failed Nazi Scuba Instructors add-on requirements you are still entitled to a certification. If he’s PADI instructor, he is required to teach according to PADI’s standards, not his own.