this is what is indicated in https://shop.globe.com.ph/products/broadband/plan-1299
LTE/DSL Installation Fee: P1,000 payable in 3 months.
LTE Wireless Landline Activation Fee: P1,200 (P200 upfront payment, P1,000 payable in 5 months)
Get a free landline with unlimited calls to Globe/TM. Service/plan availability and actual speed may vary upon assessment.
Hope you could provide more details about the promo ads so Globe could validate.
You may call 211 or (02) 730-1000 to be assisted better in clarifying your bill as to why you incur 2799 charges