Need help for a large number of 4G WiFi Routers

Hi Guys, been a long time lurker, first time poster!

I'm looking for a reliable 4G WiFi Router for a widescale rollout of somewhere around 2000 small retail stores. I'm looking for something with the following features

• Hardware must be remotely managed
• Must be a small and reliable device
• Once we configure needs to be plug and play
• Whitelist Capability (Only certain domains and IPs should be allowed)
  

Not sure if I'm missing something obvious but I can't seem to find something like this that isn't hideously expensive! Thanks in advance for any help you can provide!