Default Used G2 question

Alright I picked up an excellent condition sprint G2 from a guy who soft bricked and boot looped it for 50$. I flashed it back stock so now it works again. The previous owner activated it on boost mobile monthly prepaid but decided to stop using the service. I checked the phones esn and it says its still activated on their account. Will the phones esn clear at the end of the month since its a prepaid plan? Sorry if this is a newb question

Sent from my LG-LS980 using Tapatalk