The landline and fibre connections for my small restaurant business is being disconnected soon (building owner's decision)

I've moved onto Vodafone 4G Wireless Broadband to keep my EFTPOS terminals running, but I'd like to keep a phone number for customers to place orders.

With no landline, are there any clever or efficient alternatives than just having a mobile phone permanently tethered to a charger lying around my restaurant?

Thanks.