Yes, you're right and we are not certain if the agreement...

Yes, you're right and we are not certain if the agreement between PLS and the Supplier has enough (if any) protection against consequential losses. Small suppliers typically aim to have back to back flow down terms with their insurance companies on a project by project basis to protect themselves against any potential liability arising from risky individual projects. The price for this insurance is always built into the total cost charged to clients. I've seen small suppliers not getting Professional Indemnity Insurance for a given project to offer competitive pricing.
Most consequential loss clauses also give protection to the suppliers in cases when the consequential losses occur due to negligence, wrongful act or misconduct of client's employees. Generally speaking, consequential losses are extremely hard to negotiate, prove and quantify.
The quicker PLS learn from this and move on, the better it is. The only leverage they have against the supplier is a brand damage this could cause the supplier.