No data during calls note8 dual sim

[Android Central Question]

Hi I have a note8 that I have 2 Sims on EE and 3 currently when I have set phone,messages and data on similar 1 I lose data when on a call and when I change the data to sim2 I still lose data

This is really frustrating and wondering if anyone can help with a fix for this.
Samsung have no idea and my mobile provider also doesn't know