I'm so sorry for your family's loss of your beloved dog in such tragic circumstances. I'm also sorry the incident was handled with so little tact by the groomer, although it sounds like they were also distressed.

In the first instance I would contact the manager of the groomers and discuss it with them. I would think that the last thing they would want is to have another tragedy like this occur. I would be asking them what changes to their procedures/equipment they are going to change to avoid this in the future and would also discuss costs with them.

If you do not get the answer you hope when dealing management maybe some one else can point you in the right direction as I'm unsure exactly where you could escalate it to