It's possible to get an ex back even if they've lost feelings for you. However, it will take some effort on your part and there's no guarantee that it will work. If your ex has told you outright that they don't have any feelings for you then it's going to be more difficult than if they're simply not responding to your attempts to reconnect.
If you want to try and get your ex back, the first thing you need to do is try and figure out why they lost interest in the first place. Once you know what went wrong, you can start working on fixing it. It could be something as simple as changing the way you communicate or being more attentive to their needs. Whatever it is, make sure that you're sincere in your efforts and that you're willing to put in the work required to improve things between the two of you.
It's also important to give your ex space after they've told you they don't have any feelings for you. This doesn't mean cutting them off completely, but giving them some time to miss you and realize what they're missing out on. If they see that you're still interested in them despite their rejection, it may just be enough to change their mind about how they feel towards you.
There's no guarantee that getting an ex back who lost feelings foryou is possible, but it's definitely worth a try ifyou still care about them deeply. Just make sure thatyou go into it with realistic expectations andbe prepared for anything.