O2 has confirmed customers using the Apple iPhone XR on its mobile network in the UK are experiencing serious issues.
Frustrated users have reported a lack of mobile phone signal which prevents making and receiving calls and text messages.
In addition there's been unreliable 4G connectivity, so you can't use apps such as Twitter, WhatsApp and Facebook unless you connect to wi-fi.
If you are one of those affected, read on to find out more information about this problem and what your rights are.
An O2 spokeswoman told the BBC: 'We're working closely with our partners to resolve an intermittent issue affecting some of our customers using iPhone XR.
'We thank any customers affected for their patience.'
Multiple users have taken to Twitter, with some alleging the issues having been ongoing since November, and some report that it started as far back as September.
O2 customer Jim Buckley told BBC news that since 16 December his iPhone XR has had no signal or weak signal, and it's not been fit for purpose so he's had to invest in another smartphone that works properly.
One user says he was told by an O2 representative that Apple caused the issue with a recent iOS update, but this hasn't been officially confirmed by O2 or Apple.
Currently O2 will not say exactly how many users have been affected by the problem, but they have advised customers to try turning their phone off and on again as this could temporarily solve the issue.
A more permanent fix should be coming from Apple, but there's currently no date as to when this might be.
An Apple spokesperson said: 'We are aware of an issue causing intermittent network connectivity affecting some O2 customers, and we will have a fix in an upcoming software release.'
Like most Apple smartphones, the XR isn't cheap and will set you back £629 for the basic 64GB version, while the 128GB version costs £679.
A standard O2 contract for the iPhone XR comes in at around £30 a month.
Which? Consumer Rights expert Adam French said: 'Which? believes it's important that O2 and Apple work together to ensure that no customers are left out of pocket by the loss of connections and that anyone who has not had full use of their phone should be appropriately compensated.'
If your iPhone XR is experiencing issues, visit our where you can find help and advice, and find out whether you can make a faulty goods complaint to help you get a refund, repair or replacement device.