Problem Logging into Enterprise Account

Hi

One of my account users was using her work email for an individual account and then requested that she have an Enterprise Account.  She needs to use the same email but it won't let her do that (it asks her to upgrade and pick a plan).  She was sent an invite to her new Enterprise Licence and it shows up in notifications but she can't action it.  She sat with our service desk staff the other day on it. This is what has happened;

1. I set up a free Lucid account to have a look with my work email
2. I realised oh, this is good, I should really be on the Enterprise plan
3. I requested a licence
4. I got given a licence
5. When I then click to accept on the licence, I still remain on the free version of the plan and my only option to upgrade is to pay myself (see below)
6. This is the case whether I log in with my work email or my private email.  I have changed my Lucid password several times on each email address but still no success logging into the Enterprise Account.  (This is similar to the Aaron 101 problem of some years ago.)