Unable to connect to 5ghz wifi band

[#1]

I have been having problems with my WiFi in the last couple of days. Firstly I was unable to connect to the WiFi at all so a rang customer services and they advised to split the WiFi, so done that and then I was able to connect to 5GHz wifi. A few minutes later the 5GHz band dropped. I am now only able to connect to my WiFi on the 2.5 GHz band. I have tried changing bands manually and this still doesn't fix the issue. Please can someone help I'm working from home at the minute and the 2.5g band is not ideal thanks.

[#2]

Try giving the 2 bands different SSID names.
Not all devices are 5ghz equipped.

[#3]

Thanks for your replI've already tried that yesterday, looks like it's all sorted now a think a firmware update might have been pushed out last night to my router.