联系当时的同事，然后看官网说明：
If you are Unable to Obtain an Employment Reference
If you are unable to obtain an employment reference on a company letterhead from your employer, a third party official Statutory Declaration written by work colleague may be considered.
The Statutory Declaration must be written by a third party work colleague; NOT written by yourself. Self-written statements submitted as a Statutory Declaration will be assessed as not suitable.
A Statutory Declaration written by a work colleague needs to describe the working relationship with you and supply details of your duties performed with relevant dates of employment. It is preferable that the work colleague writing the Statutory Declaration be at a supervisory level.
Acceptance of Statutory Declarations in place of employment references will be subject to the verification and discretion of the ACS and noted to the Department of Immigration and Border Protection for authentication against fraud and plagiarism.
Important Note: Self-written statements submitted as a Statutory Declaration will be assessed as not suitable. Self-references in the form of a Statutory Declaration cannot be accepted as evidence of employment. Statutory Declarations must be written by a third party work colleague and signed by an authorised witness to be considered suitable.
Statutory Declarations
A Statutory Declaration is a written statement declared to be true in the presence of an authorised witness.
All Statutory Declarations must be clearly signed by an authorised witness to be considered for assessment: List of Authorised Witnesses
Australian Statutory Declaration for use within Australia: Statutory Declaration
For Overseas Statutory Declaration, please refer to the legal standard within the country you are applying from.
除了同事的推荐信，你还需要以下三种文件之一作为证明，只有推荐信现在ACS不接受了。
One of the following additional documentation will be required for all Statutory Declarations or Affidavits:
Payslip – preferably first & last payslip -工资单
Human Resource statement or Service Certificate - 人力部门的声明或旧的在职证明；（我翻箱倒柜的找出以前公司开的不知道做什么用的收入证明（可能是购房时用的），庆幸啊，不然死定了。ACS还说格式不对，我跟他argue了几次，我十年前怎么知道你要什么格式，最后他们还是接受了。）
Termination Letter with corresponding dates - 离职信（有离职日期）