Yes I think you have to use the exact email address on your Paysystems Account - it is not necessarily the same as the your email address Paysystems use to email daily account balances.
Trouble of course is if you have several accounts and several email addresses you are just guessing the right one to use, and as akashik mentioned if you give the incorrect email address the retrieve password facility just says that a new password has been emailed when in fact it hasn't
I live in the UK so didn't fancy phoning, I emailed support direct giving my account numbers and my full postal address - I received the passwords back by email within a few hours.
It is very good that Paysystems take security seriously but I think a better way to do this would be to send a 'Change your Password within 7 days' notice before they automatically change account passwords without telling the account holder.
I think this would solve a lot of problems for account holders and probably save a lot of work for their support staff as well.