Unprofessional in all possible aspects!
Our experience with PostKasseStickers has been horrible from the very beginning. We bought a mailbox sticker for our new house, quite pricy but we wanted it customisable, fair enough.
After 3 weeks, it came... with a typo!. One would expect that a company selling custom sticker would be good at copy+paste from the digital form and/or would care to check cautiously. After some complaining (and more waiting) they sent a replacement with not one but two typos! One could assume a mistake in the first one, but this is an utter display of lack of care.
We have complained several times over the last few weeks. Total radio silence. We do not even want that they try a third time, just a refund... but we do not even get an answer!
Really unprofessional. Avoid them like the plague; bad (zero) communication, bad service, bad experience, bad in every possible aspect.