problems with blackberry.net

Hi List..

I'm using the debian package of relaydelay with sendmail, and it  
works great but i seem to be seeing an unusually high blocked/passed  
ratio on mail from blackberry devices.

+---------------+------------------------------------------ 
+---------------+--------------+
| relay_ip      | mail_from                                |  
blocked_count | passed_count |
+---------------+------------------------------------------ 
+---------------+--------------+
| 206.51.26.242 | <[email protected]>               
|            16 |            1 |
| 206.51.26.40  | <[email protected]>           
|            24 |            1 |
| 206.51.26.200 | <[email protected]>       
|            30 |            3 |
| 206.51.26.200 | <[email protected]>               
|            32 |            2 |
| 206.51.26.200 | <[email protected]>       
|            26 |           22 |
| 206.51.26.186 | <[email protected]>  
|             5 |            4 |
| 206.51.26.47  | <[email protected]>       
|            26 |            4 |
| 206.51.26.200 | <[email protected]>               
|            26 |            1 |
| 206.51.26.200 | <[email protected]>       
|            26 |           10 |
| 206.51.26.186 | <[email protected]>                 
|            14 |            1 |
| 216.9.246.129 | <[email protected]>     
|            13 |            6 |
| 206.51.26.200 | <[email protected]>       
|            32 |            1 |
| 206.51.26.186 | <[email protected]>                 
|            18 |            1 |
+---------------+------------------------------------------ 
+---------------+--------------+

Far as i know the mail_from's are all legit.. but i'm getting  
complaints that the mail isn't getting through. Before i throw my  
hands up and tell the users "broken MTA nothing i can do" just wanted  
to make sure it's not just me and canvas possible solutions - should  
i just whitelist the relay IPs or is there a better way?

thanks in adv,
..S.