with luv to my pet hamster Kohlrabi

So, I'm an artist, or well, I'd like to call myself one. Here's my problem, and I'm looking for some help and advice:

At around May, a customer commissioned me to draw their OC. I gladly accepted, saying that I will have the sketch done in 1-2 weeks or more, if I'm busy. The customer agreed.

A week later, I sent her half of the sketch, notifying that I'm still doing my commissions, and that she doesn't have to worry, and that I will try to finish it as soon as possible. But I had too much work to do (believe me, I hate being slow on commissions and making customers wait, so I put much effort into my work and try my best to get the commission done).

By early June, the customer suddenly messaged me and said that I was taking too much time on the sketch, and that they want to cancel the commission. They said that they did post a status telling all of the artists they commissioned that they can't receive anymore commissions in June because they're busy, requesting all said artists to comment on the post, and complained about how I never commented ( I never saw this post, or I must have missed it somehow, because I'm rarely online. I told them that they never gave me the deadline, and they said it was because they forgot my username. Wow.) . I was really pissed off, because the customer never gave me the deadline, yet they were complaining about how I'm taking too much time, not to mention how busy I in the past weeks because I had many important tests and exams .

Since the customer was being really grumpy and grouchy, I convinced myself to let her get away with canceling my commission, just to avoid trouble. As I really needed the money, I asked the customer whether I could re-sell the drawing to someone else, since it is their OC, and I actually want permission from them and sent them the full sketch.

The thing is I'm a hypocrite, and I want my commissions to satisfy my customers , so I drew the OC with the same pose - not exactly the same pose, since I only looked at their OC and imagined the pose again in my head with more dynamic and drew it, so if you take a glimpse you'll think that the pose is exactly the same, but well - it's not.

The customer accused me of tracing their art, which I disagreed to wholeheartedly, saying that no, I did not. The customer then proceeded sarcastically mock my name, and said that I'm such an "interesting" person. How I still managed to stay calm and reply them, I don't know.

The following day, it appears that the customer DM-ed their friend and took snapshots of our conversation and sent it to said friend. The friend posted all the pics online, saying how irresponsible and stupid I am for thinking I could "trace someone's art and sell it to the person who drew it". The post became viral (well not too viral, but like 100 likes or something) and everyone commented on how I'm " a cunt artist, fucking stupid, etc" .

To be honest, I don't feel ok. Trying my best to draw a commission, only to get nothing but bricks at your face isn't the nicest feeling I've ever had. I'm not sure if I'm wrong or right in this situation, and that is why I'm asking you guys for advice.

Here are the links for the drawings:

The customer's commission, drawn by me:https://imgur.com/a/gCtOwgu

The customer's original OC: https://imgur.com/a/ef1o3FI

If I'm wrong, I'll apologize to the customer for the plagiarism. But then again, I feel like it's so unfair how I didn't take their money for the unfinished commission and yet they went and did that to me. They even deleted the comments that protect me! Am I being reasonable, or just one-sided and stubborn? To be honest, I don't know anymore. My sister and my friends are still trying to report the post.

Can anyone tell me? I'm so, so sad right now. I've tried my best and this is what I got. Forgive me for my bad English, as it is not my mother tongue.