after less than 2 months to throw away

I did not originally a very cheap envelope and ordered therefore supposedly a good quality at a slightly higher price.
Now, after nearly 2 months in use I can throw away the protective sheath. gradually, the hard plastic edges that hold the phone in the envelope, canceled. At the breaking point there is now sharp edges where you can get hurt too. I have now ordered a much cheaper shell and hope that they will last longer. The description "leather" also does not apply, because the shell is completely made of plastic.