cs6 expired trial mode. Purch.direct adobe edu.vers. in 2015. Inst 653mb. Have15 #letter# serial#

Hello ! 

I am in Australia, and have been using cs4 since 2015/16  -   but can't open NEF files in it etc etc  -  so  need to fix my longterm non opening (thinks it is expired  lease version) purchased cs6  issue.

CS6 issue:

I purchased  online Cs6 educ. version (Australia) in  March 2015 direct from adobe online.

But for years it has said TRIAL is over and   won't open. **I don't think I registered it  properly on the ADOBE site. 

Also I left university  and forgot I bought it as an education  version until today -  so I couldn't find its serial # to try add  and try to open it.   

Today I contacted my old university  and reopened my emails and retrieved  the Adobe cs6 purch. emails incl.   my old  customer id +  serial number +  have my  old uni email available again.

But for   the past coupel of years   I have a new Adobe id  /  email -  and account  says I have purchased nothing from them. 

What should I do to get my CS6 to  open in my macbook ?   CS6  is in my applications dolder and is 653.2 mb / 752 items - so it is there but in a coma.

When I click to open it is wants a different length  of  serial number with a  "? " option  -

Wheen I click on   "?"  it  says if educ. version go to a uk adobe  educ site

- which when I click  and go to that it then asks if I want to  redirect to Australia educ site : yes/no

- I say yes - and  it goes to what seems  a dead end   lease CC educ. site -  with no clear means to register / add  my serial number and open  my cs6 ! . 

How can I get Adobe to  recognise my old serial number ?  and for my CS6 to open and work. 

Thanks for advice - particularly for  any step by step directions.

Julie