Double eeeewwwww!!! I would not go back to that store. I called a couple of shops here and they had NEVER had such things. I even called a shop I used to go to in FL and asked them....
I no longer wash and won't because I spent almost more time washing and ironing my fabric than sewing and I decided to liberate myself.
I know you are in a tropical area but I used to live in FL also and never had anything like that. I know the big box stores have truckloads come in and sometimes the goods are not stored in sealed, a/c areas.