Blackmagic Design interview questions

passed the interviews and got an informal offer through email and decided to accept the offer, At that point I had 2 months left until my visa expiry. I waited weeks until I got the contract and was asked by HR if I had any questions about the contract. I had few questions about process around work visa which I listed and emailed. I was waiting for the response until the hiring manager decided to withdraw the offer when only 20 days was left to my visa expiry. The company and this person did not care to elaborate any further about the reason for their action and any further communication from my side to this company was left unanswered. Just like that they decided to play with a life an immigrant who had put trust into them in his most crucial part of his life. Decide for yourself about the character and moral code of this folks and whether if you want to put any trust into these people.