I'm in almost the same situation. I bought the game at launch, and the last time I installed it was back in 2013. Last year I decided to revisit it for nostalgia's sake, but the game won't activate - neither through the in-game system nor through the EA App. At first, support asked me for the purchase receipt, then they supposedly forwarded my case to Maxis internal team so they could unlink some old account that doesn't even exist. After that, they just told me there was nothing they could do except suggest that I buy a new copy. I'm pretty sure the problem is their ridiculous DRM with its limited number of activations. The manual literally says that in cases like this, you're supposed to contact support so they can reactivate the key or replace it. Back in 2015, people actually got replacement keys - now they just tell you to get lost.
