I found this website on some article, suggesting that you don't need to enter any mobile number or another e-mail account. I was impressed. I used this website for a few years, for situations where you need a temporary account (although I didn't misused this feature). I worked great, until a few months ago when one account I had recently made was blocked. But I was fine with that.
Now I made another account, for some important work. And within a day, the account was blocked due to "irregular activity". I contacted their support staff as recommended. But the account was not unlocked. They said they forwarded my request to unblock my account, to their security department, but the account can not be unblocked and they cannot provide any further information.
Really bad service. I better find some other email provider.