I've just moved from BT mobile to EE (same company now) and was told by the BT sales team that it would be the same service with an EE SIM card and that BT Mobile was winding down. I have a Samsung S8 which has been fine with BT. As soon as I put the EE SIM card in, no data. I spent hours on the phone and an hour and a half in an EE shop. The data worked when the EE employee put his SIM card in the phone. That card was a couple of years old. I've tried a friend's and his is 3 years old. That works. My family had new EE SIM's at the same time as me. The iPhone's are ok. I was told I would be sent a new 4G SIM. EE sent a 5G and am now told that they no longer have 4G SIMs. He's technical team admit there is a problem with some Android phones and the 5G SIMs and they don't have a fix. I wish I could go back to BT but am told this is not possible. EE have offered 2 options, either allow me to cancel the contract (not a good sign for consumer confidence for their business model) or I purchase a new phone to rectify the situation. As EE are aware of this problem, customers should be made aware, particularly the BT sales staff who are all part of the same company. This issue has cost me financially through many hours trying to resolve this problem, and almost 3 weeks later, I still have no data which I have paid for.
