Lufthansa insists I canceled my ticket when I didn’t, how can I prove it wasn’t me?

If Lufthansa says you canceled your ticket but you didn't, first ask them to send you all records showing who canceled it (timestamps, IP logs, call/chat transcripts, or the email address used), because this information is very important.

Most of the time, airlines need proof that the withdrawal request came from you before they accept it.

Next, get proof for yourself, such as your check-in records, travel alerts, emails about your credit card or booking, or screenshots that show you never went to the cancellation page.

Then, send a detailed dispute to Lufthansa customer relations that includes your booking code and flight information.

If Lufthansa still wrongly says the same thing, make a complaint about Xolvie to get it fixed.