When does the pillage stop

I am not impressed with the service i received from momentum ingwe. I am a student and i paid in advance for the year according to a system that is in place and has been used by this organization before. I was however not activated on the system, because as is required no invoice was sent to us. I paid for 10 months and should thus have been covered for 10 months. Now that payment has been sorted out, momentum claims that i am only covered until the end of the year. Which is not fair! I was not activated on the system from the end of February. How can i pay for 10 months and only receive over for three months, when there was a purchase order issued and the funds only needed an invoice to be released a process that we have undertaken before with momentum! I am not impressed at all with this service, and will not be renewing my membership with momentum again, and suggesting to the rest of my department as well that alternative medical aid be sought, because this is not the type of service that I will accept.