Language barrier my friend. To him, and in translation, your words may come off as aggressive or he/she just might have misunderstood. WeChat translate is not the best. Also, “I have ordered from you with SuperBuy for more than a week” doesn’t really make sense grammatically in English let alone in a rough Chinese translation, or to someone who isn’t a native speaker. You and I understand the point, but they may not. 

Furthermore, Boostmaster Lin is comprised of multiple employees so he/she might mean quite literally you have the wrong person. As in, the person who handles this order. It’s easy for there to be misunderstandings between two people who don’t speak the same language. People need to take these things with a grain of salt.

As for him/her blocking you, I totally understand your frustration here and would be insulted if the same were done to me. Maybe he/she is having a really bad day or severely misunderstood you. I dunno.

I am not defending BM Lin’s customer service skills, or lack thereof. I am simply suggesting that there may be more to it than is portrayed here and we shouldn’t jump to conclusions.