To my knowledge, there is no monthly limit. But take note that FUP doesn't only restrict the amount of data that you consume, but also what you can and cannot do on their network. So, if you abuse the network, they can arbitrarily implement FUP.
Re: when the counter resets, they will not tell you para iwas pompyang.
Daily ang usually ini-implement ni Globe for DSL account depending on the subscribe plan. Since you subscribe to DSL Plan 1599 which has a 10GB daily data limit. Actually, walang clear information on the the reset after you hit the threshold kaya medyo magulo yung implementation nila ng FUP. According to Globe the data speed will only normalize on the next cycle either 6 AM or 10 AM of the "following day". Eto yung tricky part yung "next day", what they really mean is lets say you hit the threshold around 10AM of Oct 23 so you are expecting that your speed will reset by 6 AM or 10 AM of Oct 24 of the following day right? Wrong, basically the FUP will be active for 24 hours. Once the 24 hour FUP period has been reach that is the time you will start to count for the reset of your speed. This based on my experience, di na ako nagrereklamo since it may or it may not be our fault to reach the threshold but that is the contract that we have sign with Globe.