iPhone 7 cannot hear person calling me or when I call them ?

CANNOT HEAR THE PERSON IM CALLING AND THE CANNOT HEAR ME ? I have a iPhone 7 and cannot hear person calling me or when I call them they can’t hear me ? Speaker grayed out issue maybe ??? I Can get text and retrieve voice mail , search on line. Etc... and it’s been in and out like this for the last 10 days ?? Help!!!