I recently moved to a new apartment, I was able to transfer my internet to a new location after a couple appointments but now I have my internet and happily using it.

I received a letter with some bardcode etc. that I am guessing how to return the modem back to telekom, stating that I would be charged if I did not return. I am a member less than 6 months.

What triggered this letter? Moving to new place? or free period of the modem Telekom provided expiring? I certainly did not trigger it with any request. Please provide information and context.

Thank you