You will find that working with these marketing departments is not as straightforward as one would hope.
I think the guys that are put in these offices are put there to just kill the businesses (I say this from the premise that I sought audience with them many a time and was not even given ear as to what is was that I wanted to talk about, let alone to share my world changing, well at least for their company, idea!!!).
That being said, I would suggest that you visit their offices and ask to speak to a marketing representative, or just to get a contact person. For contact details, I have none at hand but would suggest you either call them (on their telephone numbers as shown in various yellow and white pages) or visit their offices or check out their Facebook pages. For their offices, here's my assistance:
Telone - Crn Inez Terreze & N. Mandela (They may refer you to Runhare at K. Nkurumah & 4th St)
Econet - good luck here. Most arrogant bunch I've come across. Try Livingstong & 7th or Msasa Head Office
Africom - Tendeseka Park on Samora Machel (Eastlea area)
Liquid - ZB Life Towers Cnr J. Moyo & 2nd St (or is it Eastgate, same as ZOL?)
Utande - Pegasus Hse, 9th Floor, S. Machel (between L. Takawira & J. Nyerere)
uMax - Same as Utande, they are a subsidiary of Utande
Powertel - NetOne building, think it's 5th Floor
Frampol - not too sure, check their Facebook page
ZOL - Eastgate, 2nd floor, not too sure what "Bridge", but one above Escalators.