lost iphone. find my iphone turned off

Hello,

first of all im not sure if i can say in czech so i will try to do my best to explain the situation in eng.

I moved to Bali and somebody stole my iPhone 7. I did secured it by lost mode and the iPhone was found twice via location for a few seconds. Now im asking you because after two days i cant find an iPhone via iCloud in the find my iPhone ... but if i open preferences in the column my devices, he is still there... can u please tell me the reasons how can this happen? thank you for response.

Luka5