A few things to clarify on this request.
For one, if you are using Tiles, then OSAPI is not used to update their content. You only use OSAPI when rendering the configuration screen in the browser for client-side JS (not server-side).
In order to update a tile, you need to get the service end-point for that tile and pass in the appropriate pay-load, such as this:
I'm not sure if this helps or not, but if you could pass along some more details, that might help figure out where there are any gaps.