I am able to login.
Are you using your 447nnnn to login and the PIN they sent with the email as the password (see link below)? If so, something else may be wrong. Unfortunately, a number of people have not had much luck contacting them.
http://www.prepaidgsm.net/forum/show...=freeglobalsim
Also, see if you can login here...
http://longdistancesim.host4tele.com/hosting/globalsim/
Phones: Xiaomi Mi Mix 2, Samsung Galaxy A50, ASUS zenfone 3,
Sim cards: AT&T (Contract), 3 UK, Piranha Mobile