Since I care more for the proof I even have a video of 2 of the bookings made just to prove.

It all started with SEPTBONUS campaign which I messaged the WhatsApp chat to ask why each time it said "The offer is no longer valid...", they said they would investigate and get back to me. On the 30th of Sept I messaged them again they said don't worry we're still looking into it, but I had 2 business class bookings waiting based on the campaign.

I booked my first 2 bookings on 3rd with paying 19Euro each on Hold. I was waiting to pay them based on the campaign answer. I had no luck, so I booked again and paid. Then I had to change the booking by 1 day which was not possible, even if the website advertised that my class(I) was allowed 2 changes, so the chat told me I could only cancel or downgrade to economy. So I canceled, and on the cancelation page I had 2 options "Refund" "+10% voucher", I selected 10% voucher and it showed me the amount I would get which was +10%. 2 minutes later my confirmation email says "We have received your refund request for XXXXX. The refundable amount will be credited to the card used at the time of purchase." I was puzzled so I tried to see if I cancel the other booking too it would be the same.
The 2nd one worked and said "We have received your request to exchange the unutilised value of your ticket, in booking XXXXXX, for a travel voucher. Worth 10% more than your ticket, your travel voucher can be used to fly with us from the date of issue."
I thought oh is my bad, I made a mistake... then the refund confirmation came 100% of the money paid. Which was ok. Then the voucher for the other booking came. minus 10%!!!!

I get angry and make it my mission to see what is going on. I make the bookings again and cancel them requesting a +10% voucher. BOTH getting the same message: We have received your refund request for XXXXX. The refundable amount will be credited to the card used at the time of purchase. One was even canceled in less than 1 minute after paying it. And it is very clearly advertised cancelation without fees in first 24 hours. And then I get "We have refunded unutilized amount of EUR 2803.86 to the same mode of payment you made your purchase with." While I paid 3200 EUR.

Then they say "Please note that SEPTBONUS offer/ promo was set until 30SEP23 00:00 hours and not 2359 hours." But I have screen shots of 27, 28 and 29th with the same error.

Then I got a revised voucher for my 2nd cancelation. Which was initially 10% lower than I paid, but now it was the amount I paid no extra 10%.

I check the T&C and there is this mention

• Voucher exchange is not applicable for ‘Lite’ or other non-refundable fares. NOT THE CASE
• A refund fee may apply when requesting a refund for a booking paid for using a voucher, depending on the fare rules of the purchased ticket. NOT THE CASE

Then suddenly they said +10% is no longer available for anyone it was a past campaign. And now the whole mess and 10 days of hassle, the voucher option has been disabled completely (greyed out although the booking was made and paid online).