@Aurther You can't have e-commerce (or any form of commerce) without payment. In the developed world, this is a mostly-solved problem (via credit cards); not so much in Zimbabwe. If e-commerce is to blossom, step 1 would be to solve payment.
I wouldn't look to the banks for a solution though, they are barely figuring out the whole internet thing. Unfortunately our banking laws are depressingly 20th century, it would be impossible for any non-bank actor to solve this. I hate to be "that guy", but I'm not holding my breath - not even for EcoCash/TN Bank. I think EcoCash will be internet-enabled at around the same time every Zimbabwean gets a credit card with their bank account.