Lotsa different stuff going on here, for sure. First of all, not all adapters are created equal. 1/1000 of an inch off is all it takes not to thread properly. Often times, the new vaper tightens there toppers a bit to tight. All it takes in one time, and you can damage the threads, the connection, push the pin, etc. Many have easy fixes, stripping the threads is not an easy fix. Another thing is that not all toppers are created equal. One badly threaded topper, out just 1/1000 of an inch can strip your threads. That's why the Vets recommend always using an adapter on any of your devices. I have a stainless Vamo V3. My threads are perfect. My daughter has one as well. I've already dug the remains of a Protank coil out of the 510 connection. Hand tighten sweetie, I say to her. She thinks it requires hand tools to put them on and take them off. Bye, bye threads and connection. You can mess up the 510's or the ego threads too. I have devices that won't thread the Evod's. Others that work just fine. Be patient, be careful, be gentle and vaping can be very rewarding. If you did get a bad one, you can send it back to Florida and FT has one of the best CS in the business, and way better than most US Vendors, I can tell you. Many stories about both of these on the Forum. I hope you get this worked out and good luck to you!