Probleem met Messenger bot

I have an urgent problem with my 2 chatbots on Messenger. You can find them with m.me/supersecretdasbox and m.me/supersnapdasbox When you send them a message, you don't get a response anymore. It worked yesterday, but today it stopped working. We have made a custom chatbot on Messenger, we did not use a software package like chatfuel for example. We have some Windos services Running written in C# that handle the incoming and outgoing messages with Facebook. I'm looking for someone who would have a look at this problem and see what has happened and try to Fix it as soon as possible as this is a service that needs to be Running at all times. The programmer that I use normally is on holiday unfortunately.... In general, I need an extra chatbot developer as my current developer will not be available most of the time in the coming months. So we can build up a structural relationship for the future. Who can help?