Spinwing, first a few questions.
1. Did you sign a contract with your employer, and if so was there any mention of training bonds at that time?
2. What is the amount of the bond and over what period of time is it applicable?
3. Have training bonds been used before on different types within the company?
4. Is there a clause that mentions pro-rata pay back?
5. Will your job be jeopardised if you don't sign?