Mail delay from messagelabs.com

Hello,

We had many problem to received mail from your gateway *.messagelabs.com.

The mail arrived corretly but with many delay (sometime 2-3 hours or 2 days).
It's not possible to talk with our clients with this delay.

We had few example with many clients.

I had already created a ticket on the mail investigation@review.symantec.com but he does not response since 7 days.

For example, i can send you few headers (in private)

Thanks for your help