We discussed the details of the commission over Discord, although I originally approached them through Twitter. Their Twitter was banned, and they had to make a new one. All records of that time have been lost.
Original discussion went well. DR seemed happy to work on the pictures and when I mentioned it was a friend's birthday, they said that they would hurry them up.
The first sketch was delivered in a couple days. Immediately after this, however, DevilRush disappeared from the internet for over a month. There are unfortunately no records of this, as their twitter was deleted after the fact. From gathering information from other people who had commissioned them, it appears that DR took the money from opening 20 commission slots and used it to buy themselves a new tablet. Then, they took on an undisclosed "big project" for their college and had to devote 100% of their time towards it. I messaged them over twitter several times in the next couple months, but got no response.
After 2 months of radio silence towards me, DR started posting personal pictures to their pixiv and new Twitter. After confronting them about this, they said they hadn't forgotten and had been working on other commissions that they'd not posted publicly. They also offered to pay me back the price of the commission after it was done. I declined, saying I just wanted the commission I'd paid for.
The last correspondence I had with DR was on October 24. Since then, they have been dipping in and out of Twitter, posting old images. Recently they've posted WIPs of personal works, which prompted me to message them again. I have not received any response as of December 8th. It is too late to issue a chargeback, and I am completely done.