Apps can't track your IMEI or any other identifiers where you can uniquely track users with.
If I interpret Apple's developers documentation correctly, identifierForVendor (the property apps can use to uniquely track devices with) changes after deleting all the apps from that same vendor (the company that publishes the app) from a device and then re-installing them.
It is highly likely that your IP-address is what triggered their system. From a software developers point of view, that is the only value you can easily retrieve and uniquely identify user's with, because Apple simply does not have control over the network an app uses to connect to a server with. That and your photos. But you can easily misguide their assumed use of their image hashing algorithm by cropping them a bit differently/adding pixels and removing metadata.
They could use location coordinates to uniquely identify users, but I assume that is highly unlikely because that would trigger a lot of false positives if you would use the app in a place like New York.
@GN44, try it again and be aware of your Wifi usage this time. I know Android has an option where you can force specific apps to only use your cellphone data, so check if Apple also has that option.
Try to avoid a service like Datingzest. You simply would not know if those numbers already have been used by someone else. I do not live in the US, so I don't know how easily you could get a prepaid sim. I would advice just getting one instead of using a service like that. I would think buying a new prepaid sim (you need no data for it) would be cheaper. However, I'm not from the US, so I'm not sure.
Also, create a new Gmail instead of using a temporarily e-mail when creating a new Tinder account. Those domains from the temporarily e-mail site may be blacklisted as well.