Sorry to hear that. March 28 is really too long for CIC not have it yet.
If CIC is saying they don't have it your only recourse is to try to get somewhere with the DMP.
I would ask to speak with someone in charge at the DMP and explain the problem nicely
Maybe they can give you a confirmation that they sent it on March 28? or better yet, resend it to CIC.
Hopefully they're willing to help