I want to return my 5G Wlan device and don't want to start the contract.

Hi, so I ordered O2 myHome WLAN 50Mbps with 24 month contract. 

But I am moving back to my country after two three months and don't want to start this contract. 

I received the box today with device but I haven't opened it or activated it.

Can I return it as it is, without activating it and safely cancel my order and be out of officially starting a contract? N I hope nothing will be deducted next month? 

Since I'll go in few months I don't want to be in a contract anymore. 

Thanks,

Sam