It could be a problem with Simone's phone?
Does it happen on all calls in all areas?
Have you got a case on the phone?
If you're not happy you can get any Apple store to check it for you and they will replace it if faulty.
O2 will also replace within the first 28 days.
Fingers crossed you get this one sorted @Sarah1932! Please give us an update once you've spoken with Apple.
→ COVID-19 support - Help and support from O2 during the lockdown
→ Access for You: Registration - Find out how to register for our Access for You service.
→ Just joined the community or thinking of registering? Check out this handy starter guide!
→ Have a query about your account? login to My O2 for help
If you'd like to take part, why not register?
Track usage, upgrade and get support with the My O2 appDownload My O2