Cancelling homespot

Hi, 

I am planning an international move in a few months and therefore will need to cancel my homespot. I’ve had it for approx 3 years so am beyond the terms of the 24 month contract. Unfortunately I have never been able to succesfully log into my online O2 account so I can’t check any details there. 

Could anyone tell me the following:

1. How much notice do I need to give to cancel? Ie, how long before I leave should I request the cancelation
2. Will I need to send the homespot back? 

Thanks for your help!