Thank you very much. Do you know how i can contact and send those files back?

Even with a new visa/ cas number/ sponsor, I would still have to inform this to UKVI. Could it be that I have renewed my passport causing this slight mix up?

Yes, i have the visa attached to my passport already, and have used that visa to enter the UK recently (I am in the UK at the moment).

Dear all, Today, I have received a letter of curtailment after I finished my bachelors degree (june 2014) from a uk university. The thing is I am already doing my masters in another institution with a new visa/cas (applied for it on aug 2014). I wanted to ask if the letter of curtailment is valid ...