¡Very disappointed with ZOHO COMMERCE!

¡Very disappointed with ZOHO COMMERCE!

We are very upset with Zoho Commerce.
We have created an application and we are facing a lot of problems to connect Zoho API, in fact the API is incomplete.
The login and registration area is impossible to show in our APP.
After a month of exchanging emails, they have stipulated a period of 3 weeks to update their records, but they have not complied either. Now they request 2 more weeks without guarantees of being able to have that updated information. We invest a lot of money annually for the full Zoho One + 14 agents package and Zoho does not give us any solution. 
Our APP was supposed to be launched this month as it is the beginning of the sales season and now we will be delayed because of ZOHO.
We are very disappointed. I do not recommend anyone to try to make an APP from ZOHO Commerce.