iPhone 6S volume, earpiece and speaker

ive had my iPhone 6s for 11 months without issue until redently

the call volume through the earpiece has been getting lower to the point of being almost unable to hear anything at all. It's fine with speaker or EarPods but not normally. I've tried the suggested actions of checking the earpiece is clear, turning off noise cancellation and turning on hearing aid etc but it's still not fixed

IVe ice also noticed a similar issue with the main speaker when playing music or videos, the volume is lower but also beginning to sound tinny and rattly, not the quality of the music I have on there. Everything works as it should through EarPods or my blue tooth speaker

aany help please? I've tried to take my phone to my nearest Apple Store but they couldn't get me in and I've tried booking but cannot even get an appointment