Maybe it's not the private key, it's the refund address I receive my funds on, so not really sure what I can do with it? Is there any contact or support I can find in order to help me retrieve it or?
First off to avoid confusion: private keys have 51 or 52 characters[1], addresses won't go above 35 characters[2], and public keys are longer than 60 characters[3]. Seed are combination of multiple
words. Entering addresses or public key will only get you a watch only wallet.
Examples:
[1] 1BGnMnu1g9R3wxJqZSqrDNv7ps1yLEzAaW
[2] KykaDLDJN5ZY5HYJDBoedHhQDMYsye5LRbqgefDAdoNhgqzNbYhT
[3] 02f76913e7f1ac86c096621420fcae968a276e892f2b2b0304c9d8a717e9c08e87
Also, people can try to help you get your coins back on your own, but they won't get it back for you like some services support do.