The ZESA tokens purchases via EcoCash is not working as advertised right now.
The mobile money service provider sent out the statement below making it clear the problem lies with ZESA's system:
Dear Valued Customer
You may experience service
disruptions in trying to purchase ZESA prepaid tokens as the ZESA token
purchase system is not stable.
We are working with ZETDC and
Powertel to resolve the technical challenge and we will advise you as
soon as normal service is restored.
We are pleased to advise that all other services on EcoCash are working.