Hello @userhtbxnT8yAF , I'm sorry your dealing with such issues and id be glad to assist you in this matter. In this case your best option would be to contact samsung directly as their are no service center that will physically service the phone onsite but you can contact 1800-samsung (1-800-726-7864) or also click the link below for multiple ways of contacting Samsung. You can mail your phone and see what is, if you like you can wait and a certified technician will be excited to run a diagnostic for free and let you know how much it would cost, if their is even a cost to begin with. I hope this was helpful and any questions or concerns we are here to help. Have a wonderful day!
So one thing you can try is "Reset Network Settings" and see if that helps.
Also, make your your speakers are clean and free of debris. A small soft brush should be just fine.
Hope this bit of info helps in any way.