Unfairly treated

I'm a student of Intec college I'm not certified the way they treat me after I have paid all their money .the course was taking 2 years but I did not pass by that specific time as I'm working I asked them what is going to happen as the duration time is finished they said I will pay when is the time of examination per module and I was fine with that now this year I did 5 assignmebts for organisational psychology one day I noticed that two were deleted unread when I asked they said it's out of agreed time for course whereas nobody told me that they charge per assignment when I called they take me pillar to post I'm just asking about my assignmdnt why where not marked before March until now nobody is telling me something tangeanle I'm sick and tired I'm not sure I will have this qualification