Last december 2017 i had a vacation leave until jan 2, 2018. Upon checking at the ticketing booth all vessel bound for Cebu are fully booked. I immediately informed my supervisor last dec 29 2017 regarding this and ask permission if i can go back to work on jan 4 2018 instead of Jan 3 2018 since the airline ticket on Jan 4 was much cheaper and yes, she approved it. When i got back to work last jan 4 i immedietely filed an absent form since it is the protocol of the company. Now the HR department notified me to make an explanation letter regarding that and they charged it as an AWOL. Is it right that they considered it as an AWOL even if i notified my supervisor and filed an absent leave? What should i do? How can i argue this matter to them?
Thank you