why is my volume changing when headphone is in?

[AC Question]

Hi
Ive had my g8 huawei phone for 3 weeks now and always used the headphones for 5-8 hours a day.
But today i was listening to music and after 30 minutes or so i noticed the volume going down until it reached zero when i looked at my phone i found that the volume bar is going crazy and it also lowered the phones volume itself i thought that i pressed the volume button by mistake but it was still doing so when i layed it flat.ive searched for solutions all over the internet but no one has the answer
Ps.i use the included headphones

 

[B. Diddy]

Welcome to Android Central! Check the headphone jack to make sure there isn't any debris in there. Blow it out with a can of compressed air.

Have you tried other headphones as well?