JOINING TIME — EXTRACT FROM CIVIL SERVICES RULES (CSR) PUNJAB (VOLUME – I)

Aoa. Respected Sir, i m doing job in public univerdity of Punjab. In 2013 I am selected as Assistant/ Head Clerk BPS-14 from my previous post Lab Attandant BP-2 in the same university. I have received appointment letter on 07-5-2013 and same day i have joined. But my other colleagues joined on 06-5-2013. Now in 2020 all are promoted in next scale except me. Is there any law of no need of joining of employee if he is selected in higher post in the same university ? Please guide me in this regard.
Regards