What could be causing my mic for Siri not to work?

I am using an IPhone 6+ with iOS11.2.2 and I have recently noticed noticed that when I try to talk to Siri it isn’t picking anything up so I tried with my other things that use mic.

Voice recognition, front camera video, speech in text and FaceTime/third party video call apps will also not pick up my voice.

If anyone knows a fix that would be helpful but don’t planning on taking to apple to get fixed and ohone is no longer covered and I don’t have the money to pay.