Voucher code made illegible?

I bought a voucher card for Xbox. Unfortunately, I was too stupid to scrape off the code. I thought that you have to pull the peel off. But I only realized too late that it was wrong. Half of the code is in the scraps of paper. That was a 50 euro prepaid card and I don't know what to do now. Does anyone have any idea what to do now?

I would cover letter from the company and ask them for help. Otherwise I would just go crying.