Samsung Grand 2 voice issue

Hello experts,



I brought samsung grand 2 last month, basically I am in UAE and use to call to my family back there in India through internet calling.



But since I buy this phone, whenever I am making call through internet.



Through speaker only I can make a call, if speaker is not open then call is connected but I can not here nor other party can here me. so speaker must be active.



Apart from internet call, any other call like local I can use my phone normal, no need to activate speaker.



I have checked all setting about phone, but nothing help me out. Went to mobile shop and told him this problem, as a solution he suggest to uninstall antivirus software from phone, I did this but no result.



If someone can help me out is really appreciate.



Thanks,