I tried to return something, but I was signed out when I bought it.

So I don't really know what category to put this under, but i have a real issue. So, I bought the USB Power Cable with Long-range Wi-Fi® Receiver, thinking it would be MINI USB because that's what is in the picture and that's what my old gen Roku Stick 4k+ uses. Turns out it was a micro USB instead. Now I need to return it but, that's when I realized I wasn't signed into the website when I bought it. You can't return easily if you weren't on your account when you bought it. I have contacted support about this and they said they would send me an email or just didn't solve my problem or help. I really just want my $20 back (which is absurdly expensive for one cord). So if anyone has a solution or knows how to help, feel free to answer.