452693 API & Database Debug Errors

Hello, My website is complete and running. I sell funeral flowers online. I am an affiliate for my vendor. Basically when someone checkouts to order there funeral flowers they have two options to checkout using the platform of opencart. Guest checkout or registered account. Once they select they enter in all there information and enter in there credit card information on my system, then when they hit continue it sends all this information to my vendor by an API and my vendor returns the floristid number to show me as a confirmation. All this is setup and working, the problem is that some orders go through successfully and some do not. The system after everything is done makes the customer think the order went through successful but that isnt always the case, which is a huge problem. I have the document from my vendor with all the API database information and basically I am looking for someone to go in there and review all the API and database and see what is causing this to occur and fix it. I have system all setup correctly and in admin panel of my site can see where it returns the florisid number successfully or not. Just not sure why some of the orders arent going through right? That's why I need you. Looking for someone with a lot of experience with opencart program and working with API & Databases.