Monthly Recurring Fee (MRF) simply means the total fixed amount billed to you every month net of the 12% VAT imposed by the BIR. This is usually the plan you subscribed for (In your case Php 1,100 less 12% VAT).
Your total bill may be higher as Globe might have added a prorated MRF to adjust your actual availment date with your regular billing cycle which is usually the case for your first bill.
There also might have been charges for excess usage of your consumables or value added services which are billed on top of your plan. You may want to post your billing statement (name, address, account and phone number deleted for security reasons). so that we would be able to explain more.