Answered question
What should I do for unused travel data? Can I transfer the data to another add on travel region area?
You cannot change regions since the tarifs are different for each region. The add-on expires at the end of the next billiing cycle. Unfortunately there is no refund for add-ons.
Other answers
I think that data is gone :-(
But it might be worth it to contact them just in case.
The travel add are not refundable and that's they will answer you. I know that because the question has been asked in the french side an à Whizz gived this answer.
Unfortunately once you've bought it, if you don't use it, you'll lose it after the following plan renewal.
Fizz support cannot provide refunds for travel add-ons.
Short answer is no. Travel add-ons are good for current billing period and next.
However, funds in your wallet can be transferred back to your payment method.
No refunds for travel add-ons. They will get lost.