Hello Michael,
To receive more accurate advice, it will help if you provide more specific information such as the country that you are located in, the country that the client is located in, whether the payment involves international exchange, etc., whether you have a contract with the client that specifies the details of payment (method, timing, and route of payment, etc.), and whether the client is an agency or a direct client. For example, sometimes agencies experience a delay in payment from their clients, and if they are just starting up, they may be operating on a shoestring budget. Moreover, most new companies are not members of BBB.
Is the PM still working for the client? Is the name of a supervisor listed on their website? Possibly it is an honest mistake rather than something more sinister. Legitimate clients, especially agencies, need translators as much as translators need them. There are also scammers out there, but at least this client is offering payment rather than attempting to disappear.
I hope you can resolve this matter, and you can consider this a good learning experience as you continue your career as a translator. Please let us know how you resolve this.
John Stroman