Having Tier-4 and ECAA(Business Person ECAA/Turkey)

I am currently in the UK and 2nd year PhD student. While I have a TIER 4 visa valid until the end of 2018, I applied to a visa called Agreement (ECAA) with Turkey visa to start a business. I applied by consulting with university welfare office in which I have been told this ECAA visa type allow to study and business at the same time.

I completed all my documents and applied ECAA visa by getting permission from both welfare office and my supervisor. When I received my new 12 months ECAA visa (valid until march 2017- this visa given first for 12 months than for 3 years), my tier-4 visa (the one valid until 2018) was still on my passport.

I was expecting to be taken of my visa, and consulted to welfare office. They told me 3 months ago that either both of them valid, or you should get a letter in a few days which says Tier-4 is not valid anymore. However, they also said education visa can/may be still valid as it is longer one from both, and they are separate vises. Additionally, they also told me that if you apply a 3 year extension for ECAA and rejected, you should stop all your business and no make any money transfer anymore with Tier-4 as it is a visa type does not allow to run a business.

Could you help me to understand whether both is valid, or not? because welfare office told me I am the only student in this university history who applied ECAA while still in PhD and given a visa.

Please answer my question if you know something about it.

Simple answer - your last grant of leave superceds all other grants of leave and cancels the previous visa.

So in your case with a successful ECAA visa that now sets the conditions of stay and resets your expiry date to the new visa date.

Hello taasdegis,
Have you been able to learn more about your case? Do you know which visa is valid now? And I understand that you have your ECAA visa now, but you continue studying at the same time? How did you explain that in your application? Wasn't that a concern while you were making your application? I mean studying full time and setting up a business might lead the caseworker reject it, but that is great that you have your ECAA visa now

Are you a self-funded student or are you on a scholarhip?
Thanks in advance...