Quebec student loan tax letter?

[misswan]

Hi Forum,

 
Posted here before regarding SSHRC, but this time I have a pressing question regarding a letter from the AFE (Quebec student loans). 
 
They've requested a letter from me due to a discrepancy in my application a few months earlier and my recent tax submission. Has anyone else received this and might be able to clarify what they're looking for? 
 
The letter states:
Kindly submit the following documents so we can make the required corrections to your file... you need to clearly identify the source of all income reported on line 154. Upload documents:
-a letter explaining the differneces that were found
-prov and fed tax slips issued to you by employers, gov ministries and other bodies, institutions etc
-your fed and prov assessments
 
Thank you to those who can shed some light.

Edited July 12, 2015 by TakeruK
removed non-relevant personal details