No outbound calls, need a new sim?

[Genhm]

I cannot make outbound calls, have little to no signal when not connected to WiFi and cannot receive incoming calls without WiFi. 
I have had two dubious calls from 'sky' stating I need a new SIM card. I couldn't complete the calls at the time, plus I thought it was a scam, but now I cannot find an option to order a new SIM card and cannot make a call to sky either. Please help.  Thanks in advance

[caesarome]

@Genhm 

The calls would have been from a scammer who is only interested in getting access to your account to order a phone or tablet from it.

If WiFi calling an option for you when at home ?

[Genhm]

Thanks, I'll look into WiFi calling. But I would really like to be able to use my phone when I'm not at home. 
is an eSIM any good in your opinion?

[caesarome]

@Genhm 

I've never used an eSIM but they should be no different than a SIM card.