When did you submit , Can you give your full timeline ?? In all likelihood at the time you applied Academic IELTS was accepted but that is no longer the case.
The reason i see why they do it is that language points are very crucial for most applicants so its actually a benefit they are giving to applicants e.g if someone gets 16 points in general might not be able to get that in academic one and it is then unfair to compare one applicant's points with another having different form of ielts and they want to have one scale of marking people
The way i see it,you need to retake again the ielts.Like what happen to my friend,he pass his Ielts result 2 days before it expire,and unfortunately,he was advise to take ielts-Gt this time.It was before june 26,2010 he submitted also his documents.
This was from kimwaynes post...
It was clear that when CIO received the file the IELTS result is already expired.. when it was returned, they were advised to sit on GT module instead.