SIM USELESS NO INTERNET UNLESS IM NEAR WIFI? WANT TO CANCEL CONTRACT NEED EMAIL COMPLAINTS

[Debra1234]

My SIM does not work in my phone since I started the new contract in June 9th no data has been used !!I have been trying to get some support for three weeks now to no avail. I have had three new Sims sent out and non of the work unless I'm connected to WiFi!! I need an official email to make formal complaint in order for me to take my case to the ombudsman 

[SP70]

There is no email as such. I would recommend using the complaint form https://www.three.co.uk/support/complaints/how-to-complain