Hello Markus,
To contact the Technical Support team directly, please file a service request. MATLAB Answers is designed to be a community resource for sharing information and helping each other, and is not really a way to directly get in contact with MathWorks. Some members of the tech support team or other teams at MathWorks, such as myself, may view and answer questions here, but it is not guaranteed.
In the case of your specific question, I'm not entirely sure what you are asking. If you are looking to create a ROS service server in Simulink, and react to service requests as they arrive, that functionality is not available right now for Simulink. You can create a service server in MATLAB, with a callback to react to the requests, or you can create a service client in Simulink to make those requests.
Part of the difficulty in using services with Simulink is that they are two very different paradigms of programming. Simulink is designed to be executing tasks in a loop, working on a regular cadence. Service and action servers, on the other hand, are reactive, only executing their tasks when new information comes. Services in particular are tricky because their calls are designed to be blocking, executing their tasks while stopping further execution until they are done and return a response.
If you are trying to accomplish a specific task, contacting technical support may be a good way to get some advice on how to work around this limitation or go about getting similar functionality in a different way.
-Cam
