Its not "free", its traffic-quota restricted!!! This is what they send me by mail:

Our accounts are free until a certain daily limit, then your account will be blocked until next day. This way we plan to give fair free service for all our clients.
Your account will be enabled 2018-Aug-13 19:19:11 GMT (London Time) automatically from our system. You will receive sepearate email about releasing your account. You can start using your account tomorrow at this time again.
You have generated 1037 MB traffic but at this time you are allowed to make maximum 1000 MB.