I have an Oukitel K4000 phone that supports the LTE network in the 800/1800/2100/2600 MHz bands. I live in Sušice, where the band is 800 MHz, I had a new SIM card sent by Vodafone, but the phone still does not load the 4G network and only runs on a 3G network that has quite poor coverage or 2G, even though 4G is set as preferred. Please help.