I hijacked this from another forum and it worked for me using online chat is to get BIS for only $10 extra a month here it goes
Sprint BIS for $10. Works with SERO!!! I know some people have been having trouble adding Blackberry Internet Service (BIS) to their SERO plans. Well I was able to do this yesterday without any problems!!!! Just call and tell them to add code PDSBKBISC to your existing SERO plan.
As with every other Sprint deal if one tells you no or they can't do it..... KEEP CALLING!!!!. You will eventually get someone who knows how to do their job.
SOC = PDSBKBISC
https://www.sprint.com/webconversion...thing_Plus.pdf