First Post Office Shut out- Sullivan's Island SC

While Tina and I were on our way to Fort Moultrie on Sullivan's Island SC today, we passed the Sullivan's Island Post Office...

Aha, says I, I can get an unscheduled Post Office stop and cancellation.  Went in and requested my cancellation to be told that they didn't do that, unless a letter was to be mailed.  I said fine, may I have a postcard please, to be told they didn't have any for sale.  I will be writing the Postmaster or Postmistress of this fine Federal installation to make an inquiry and see if I can in fact get a cancellation-=  the USPS in Sullivan's Island is for sure not about customer service!  Another fine example of why not to have unions.