It's a scam, there are no jobs in Dubei that pay that much. That's the first problem. The second is the lack of communication from the school, i.e. interviews and such. The third is that they want you to send them money to get a visa done. Lastly, visas don't cost that much money.

The truth is you have gotten an offer that is far too good to be true, is it likely is not true. I can tell you this is a scam, and a very common one to tell the truth. Many places pretending to be schools will ask for money upfront for some incidental, often the visa. They hope that you will not investigate, and they bank on your ignorance. It's a good thing you came here and asked some questions.

The answer is, it's a scam, it's not a real job. No real job will be asking you to send them money. Even were you required to get the visa yourself before hand, they would have you do the work, and send you the documents, they would not ask you for money. Or they would wait until you got there, and it's never a good idea to go to any school without having the proper visa first. Sometimes it works out, often it does not.

Do not speak with these folks any more, they are not a real school, just scammers looking to steal your money.