Gift stuck in mail for past 20+ days

On Sept 12 I was a low level player and a high lvl player helped me as well as gave me a Gift in the mail. I was unable to retrieve it but assumed when I was higher level it would allow it to be removed and that has not happened. The gift is stuck, I can not retrieve it nor can I send it back, and I absolutely do not want to delete it because I don't want this players gems to go to waste.

Is this a common issue and how is it resolved?

Have you reached a level high enough to unlock that item in merchant, you have to be a particular level.

If for instance, it is an instant kill buff such as assassin they are level dependant, so as Dorotheus said, need to check you are high enough level yet.