I've brought a Samsung s20 fe second hand phone

[ihatecovid202e]

Need help 

Where I've brought a second hand phone the number under the message center is different to my mobile number I've done a full factory reset and that's not worked I've chatted with support not so much help can anyone help 

The message center number won't allow to be clicked on and it's not my number on

 there 

[OmegaMutant]

The message centre isn't supposed to be your number. It's the number set by provider that allows for SMS to be sent.

[ihatecovid202e]

It's not allowing me to send SMS but I can receive them and make calls and use data

[AndrewL]

@ihatecovid202e: What options are available to you when you tap on 'Input mode', and have you tried selecting an alternative input option to see if this resolves the issue? 

In the meantime, please try inserting your SIM in another compatible phone to see if the problem persists, as this will help to determine if the problem lies with the phone, or your network/SIM. Alternatively, please try using another Messaging app e.g Google Messages. To set it as your default app, head to Settings > Apps > Choose default apps > SMS app > Google Messages (Blue speech bubble on a white background).

[Robin999]

Just contact your network provider and ask them to send you the sms/mms settings. You may even be able to request them via their website...save you a phone call.