Dear Samsung Member,
Greetings from Samsung Customer Support!
Please be assured and to resolve "internet" issue kindly follow below given steps:
1) Reset Network Settings:- Go to apps screen >Settings >General Management >Reset >Reset Network Setting.
2) Check Network mode and set it to Auto Connect. (Settings > Connections> Mobile Network> network mode SIM1 or SIM2 > Network mode> Select LTE/3G/2G auto connect).
If the issue still persist, we request you kindly visit service center as your device needs physical inspection. To check for the nearest Samsung service center kindly click on the link: https://www.samsung.com/in/support/service-center/
Thank you for writing to Samsung.
Samsung Customer Support