Thats better, but a hint, when you post code, go back and hit the copy button and copy it into an Arduino sketch to check its OK.
I dont use that particular LoRa libray (I have my own) but your post says your trying to use the " callback function " and the API guide for that library says that to use callback you need to define it thus;
LoRa.onReceive(nameoffunction);
Do you have an onReceive() in your code ?