But later on I find out that their was no way again to login.
You got scammed and they probably stop their operation after successfully scamming people, you included. Sorry for your loss, I hope you learned your lesson and never trust online mining ever again after this. That scammer is probably gonna launch another service so do watch out for it.I have been mining for 4 years, developing the farm, updating it. As a result, there was a short circuit and everything burned down. I certainly made a certain amount of money, but it's not millions of dollars. 
I don't think this is exclusive to crypto mining though, more like you need to be careful when doing electronic maintenance. If you mess with the wiring or something similar, any electronic device can break down. Visit the mining boards if you want to ask for suggestions or guides on your RIG maintenance, CMIIW. That being said, mining is obviously not for everyone if your goal is to get profit. You need a lot of capital to start and patience to wait until you get your profits. If you don't have any of that, don't try to mine or use a mining service since most of them are scams.