Premium service for 10 year ILR

I applied for ilr on the base of 10 year route
7th of October I have an appointment in Liverpool Home office
I had my fingerprints and been told for wait
After 4 hours approximately case work told me we have a make some more enquiries about your documents , we are holding your all ducuments and let you know through post.
And she gave me one formal letter, same wording written on it
Any one knows, what they gonna do
I have very clean immigration history
I was student from 2007 to 2012
Then I got tier 1 entrepreneur visa in 2012
December 2016 I got extension on same route
Now I applied for ilr on the base of 10 years
Thanks in advance

Standard practice. There might be a need to investigate your business activity and genuineness under Tier 1E before granting ILR

Many people are been put on hold the one who got passport with them and the one who varied there application God knows what the Home Office is up to