First of all, we must determine whether this training is professional and technical training. If it is ordinary on-the-job training, there is no need to pay.

Secondly, as you said, the amount of compensation was not indicated when A signed it. The company said that the training fee is 30,000 yuan, which requires formal invoices, including the fees of formal training institutions and the invoices for meals and travel expenses. If you can't issue an invoice, as an employee, you should not recognize the amount of training fees.

In addition, it depends on the agreement on the liability for breach of contract in the service agreement. How to bear the liability for breach of contract? If there is no specific agreement, I personally think it is unnecessary. Because from the point of view of whether to stipulate liquidated damages, it will completely affect whether I sign a service agreement as an employee. Since you didn't agree, you should consider that there is no penalty.

Finally, the above is an excuse from the employee's point of view, but according to personal experience, if the service period is met, the unit may make appropriate compensation.