Who to contact regarding exit date stamped in passport?

I am a British citizen currently in Tuguegarao (northern Philippines) with no way of getting back to Manila to catch my return flight to UK on 21st March (all domestic flights from Tuguegarao, buses and other road transport are cancelled until mid April). The international flights are still ok, and you can enter Manila with a valid international departure booking, but I can't get to Manila.

We took a 12 hour bus to get here yesterday, and new quarantine rules were announced during our journey. If we had known we would have travelled to Clark instead which offers international flights, whereas Tuguegarao doesn't.

The British Embassy in Manila phoneline says it's closed even during opening hours, the airline (PAL) phone lines are unavailable and the foreign office in the UK are also not answering after holding. As a result it's likely/realistic I'll be here for a few more weeks. In principle that's fine - I have a safe place to stay and should be ok financially. I can also work remotely.

However, the stamp in my passport (as a tourist) has an exit date of 8th April, which is before the earliest date I will be able to travel back to Manila unless the current situation changes (which is possible). I know there are relatively harsh penalties for staying in the country after the visa exit date has passed, but also these are exceptional circumstances. Who can I contact regarding extending the exit date? Or should I just wait until I eventually take a return flight and see what they say at the airport? I can't risk being banned from returning as I have family here.

Thanks