nobody can cancel transactions or addresses, but you can just ignore this address.
The addresses that are generated from your seed will always be the same and they will always be in the same order.
So, for example if you've used address No. 5 before a snapshot, it always be generated as No. 5 again.
Your attaching this used address to the tangle is not an accident. In fact, you HAVE to generate all your used address before you can have any new, unused addresses to be generated. So it's perfectly fine to generate and attach all your used addresses and have them appear in the addresses-list in the "History"-tab of your wallet. We all have those and it's how it's supposed to be.
The important thing is to not re-use these addresses ever again to receive new funds to them!
Just generate as many addresses as you've used before a snapshot. Then only receive to addresses that are generated after your last used address.
In the future, the Trinity wallet will take care of all this automatically and there will be no need for the whole procedure after snapshots.
Until then, maybe this will help you understand: https://forum.helloiota.com/4659/How-do-I-prepare-for-a-snapshot
I wouldn't be able to help anyone without thetangle.org-explorer. If you feel like you want to support its developer Mathieu Viossat in maintaining his service, please consider a donation to the address shown here: https://thetangle.org/about. Thank you!