Huawei P Smart not connecting to internet and microphone broken

How can I get a new/replacement phone without having it sent it off as I cannot do without it.  There is only an intermittent connection to the internet when on Wi-Fi or 4G.  Airplane mode is off.  also the microphone is broken and I can only use the phone when it is on loudspeaker.  The local O2 shop cannot help!