internet issue

[Neo7]

I am using m30s from more than 9 months but from 15 days the internet in my phone is not working properly. Sometimes it show E signal and on other hand when it says 4g LTE and 3 bars the internet doesn't work I tried everything even factory reset. 

And sometimes 4g and 4 bars but no internet 

And when I went in customer care of samsung they said this is sim issue and haven't even check my phone and in Vodafone care they said same thing your device have problem. Our sim has nothing to do with this issue 

[Neo7]

doesn't work at all

[cs-member13]

Dear Samsung Member,

Greetings from Samsung Customer Support!

Please register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).

Thank you for writing to Samsung.

Warm Regards,
Samsung Customer Support

[ramadhanedwar]

try to lock LTE Only .

here the method 

how to Force 4G LTE ONLY on Samsung device. Using FORCE 4G LTE ONLY 202O APK.

DOWNLOAD it at Galaxy store :

http://apps.samsung.com/appquery/appDetail.as?appId=com.teknokia.force4glteonly

Or at google play store : 

https://play.google.com/store/apps/details?id=com.teknokia.force4glteonly

Make sure using SIM 1 as mobile data connection default. 

[Neo7]

when I use LTE only app . calling doesn't work