Tweaking the integration with 1C site on Bitriks.

At the moment the exchange is made with errors. When exchanging only the changes are mashing the data entered through the admin panel with no change. The rubbing is produced as if produced a complete exchange. One section of the site is generally not exchanged. There is the upload file from 1C. Side 1C is a programmer. 1C Standard of 8.3 (11 configuration). Need tweaking and fix any errors. Looking for programmer with experience.