Why is my iPhone showing no service for over 3/4months now?

apart from contacting my carrier then

if it was me then I would

try restarting the ios device Force restart iPhone - Apple Support and check if it resolved it if it did not

then I would try Restore your iPhone, iPad, or iPod to factory settings - Apple Support - Apple Support if that did not resolve it then I would

contact apple about repair Contact - Official Apple Support

Look here -

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

oyibo18 wrote:

Why is my iPhone 8 showing No Service for over 3/4months now, even when there is SIM card inside it?

Because you haven’t made an effort to resolve the problem. See the link in the post from Kurtosis12, and if you still have questions reply with where you ran into problems.

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