the 599 is the plan that you avail, once there was a transaction of calls & text to other network -you will be charged on top of you 599 plan & the unbilled charges that was reflected on your account is the running usages once you exceeded your data allowance that you use after your cut off date & transaction of calls & text to other network.
Ex. FOR DATA
your COD (cut off date) is every 10th of the month
From 6/10/2016 to 7/9/2016, from that billing cycle the amount of 202.14 will be reflected
try to call the hotline (211) to clarify if the said data is used up..
advised also to monitor always your data allocation thru GServices or by *143#
as of the moment i am not sure about the status of your bill but if it is your first bill i supposed that includes the pro-rated amount and your advance payment of MRF
the pro-rated amount is the charge of your account from the date of activation until your bill cut-off