Hello everyone. 
I'm trying to understand how to proceed, can someone please guide me?

1 - I'll be leaving Germany by the end of October. When should I cancel my MagentaZuhause plan? (Considering that I will still need the connection until the last days of October)
2 - Should I cancel the plan first and then return the equipment? Or should I just return it?
3 - I've tried filling out the return form online, but it always ends up in a broken page (Error 500, I guess). What should I do?

Thanks!