Advise and help please (Education Experts)

Hi

Around two weeks ago a friend applied on my behalf for a teaching role in Saudi. Shortly after that i received a phone call from EdEx telling me i have been accepted and due to time restrictions i had to sign the contract, scan it and send it to them within half an hour, without any interview, negotiations or anything. I signed the contract and sent it immediately assuming the terms would be what he stated on the phone, 20 hours contact and 20 admin, 5 days a week. After doing so i read the contract and it states its 30hrs contact 10 admin, 6 days a week, with overtime only applicable after 48. On top of all that they can place me anywhere in Saudi and move me any time. Further when my visa arrived it was only a 90 day single entry work visa, while my contract is 12 months. I am really panicking now, especially having read all the comments on the forum. I am now due to fly there on the 25th august. Have i shot myself in the foot (signing the contract) in terms of the contract hours and undermentioned location. i am really hoping that as the contract states that the start date will be determined when signing the final contract in Saudi i can have room to negotiate at least staying in the same city throughout the 12months and do the hours that i thought i was signing , i.e 20hrs contact/20hrs admin 5 days and no unpaid overtime. Also with regards to the visa dose that mean i cant leave the country throughout that period (single entry) and what happens after the 90 days. Really panicking now any advise would really help. Anyone working through EdEx please let me know how it went for you. I am flying in two days and have absolutely no idea whats going to happen once i arrive (nothing has been explained. acceptance followed by email telling me to apply for visa, followed by flight confirmation). So any advice of any sorts would be really appreciated.

Thanks

Mouse