I had a similar case with my imbalanced LZ Z03a. HCK told me make a video but how can one show if the earphones are properly balanced without some really expensive mics and all. He offered me to ship back the item or give me $5 coupon to his store. I refused both and kept the earphone, and since then try not to buy from him.
Fake Tracking numbers though is something that a lot of aliexpress sellers do. I had ordered a few tips from another reputed seller and he gave me a tracking number that soon showed shipped. When I didn't receive them for 6 whole weeks, I messaged the seller. The seller didn't reply even once and when the protection of two months was about to get over, I demanded full refund. He gave it back to me in just a few hours. The tips were discounted at the time I bought them but now they were back to their normal price. I felt really cheated and had to order from another seller at almost double the price. Business ethics of today, I guess.
Sorry for going offtopic. Hope to hear more about Senzer.
Edit: Agh, they've become expensive.