Why did I have to pay 268 plus 25 American to visit for 8 days?

I was told by my travel agent I could abtain visa at airport.When I booked in for my flight the airline Cebu would not let me on plane unless I had a visa.An agent from Cebu contacted your officials and said I had to pay 268 American plus 25 stamping fee.As a senior this is excessive given I on a limited budget.If I had known I would not have entered for short period given these excessive fees.How do I get my 268 American back.Other tourists only paid stamping fee and visa at airport.