How to solve my Vote problem?

Hi everyone!

When people use the voting sistem, they gain the reward item.

My problem:
If they use their mobile phone or another tool in same time, that is not connected to the same network, they'll gain the reward item twice, or three times. Depends on how many devices they repeat.

How can I solve this problem?

Try to revise your code in your vote check. Your vote check must apply both IP's and User ID.