I dunno about shipping from Greece but I have ordered from China and it did take a coupla-few months to arrive. Either way with covid and lock downs right now, shipping overseas seems like a crap shoot to me. I know if you're dealing with a legit buyer they tend to bend over backward to avoid a negative rating. One person gave me a full refund, without going through eBay, for a pair of speakers because one of them had a blown woofer AND tweeter, and let me keep the speakers.
Side story: they were my DefTech SM55s. I contacted DefTech to see what they could do for me and they had me send it in. I paid shipping both ways but they replaced both drivers free of charge! Say what you want about DefTech, my experience with their customer service was right up there with SVS.
Back on track, don't get too much in a tizzy yet, give it some more time. If you don't receive the product within the promised window I'm sure eBay will take care of you man. It's just a slow process. All said and done you may even end up getting both cds. I've had good experiences dealing with eBay and have gotten refunded through their buyer protection. It wasn't exactly fast, but it all worked out in the end.