I received a sign-on bonus check from a company I didn’t end up working for.

As the title says, I intended to start a job with a large corporation last week. They unexpectedly pushed my start date back after having my tools moved to their shop, leaving my stable job, and taking a week vacation to unpack from a recent move- a vacation where I ended up working 3/5 days because I needed the cash and I couldn’t afford to not be working, especially with the holidays etc. I had competing offers which they knew about. We agreed on a 5k sign on bonus and a 50% pay raise from my current rate. After they pushed my start back I took another offer to start immediately. Same offer but longer commute. Told the manager of the shop I was supposed to work for what was happening and why and he seemed understanding, and said it was out of his hands and an hr thing etc. we left things on decent terms. Or Atleast not bad terms. I feel this whole situation was not done in good faith on their part as their reason for pushing my start date was my background check- which I fully disclosed everything they cited in the interview and on the application. The thing is, this offer was negotiated two months before the scheduled start date, after I took a week vacation and finished my two weeks at my previous job.

So, I’ve been working at the other place for two weeks now but I just received the sign on bonus from the original shop in the mail. I’d love to cash it, my it would help my family and I tremendously tbh. Life is expensive, and mechanics aren’t exactly raking it in, but I did recently get a ton of certifications (hence the 50% raise). What are the chances I can cash this check? I’m the end I’ll probably end up taking it to them and giving it back but a fella can dream right?

Edit: the company I received the check from is fortune 200, the company I work for currently is very much not.