I’m facing an issue with my Samsung Galaxy A7 2018. There is no sound in the device except when connected to headphone. But when headphone is removed, there won’t be no sound..How to fix this?

I know that it’s due to the problem that the phone is in headphone mode. But there is no option to change it to speaker mode. I even tried resetting the device settings and clearing the cache partition..but no use..how to fix this?