Question about Microsoft 365 Family (German)

I bought this Family 6 licence last year (2023) and activated it for three devices. According to my interpretation, I could buy the licence again for this year (2024), i.e. activate the three devices again and use the licence for two years instead of one. But I can't redeem it because the message appears: you have already used the licence on ... .. ...... Who can give me some tips? Thanks in advance!