Thank you so much for getting in touch, we really appreciate your time.
I see you have attached a screenshot of your marker table, however, there should also be another table for maps.
Might I kindly ask if you perhaps have a table within your database called something along the lines of prefix_wpgmza_maps? This table will contain the map data with which the markers are associated with.
If you are perhaps open to providing a temporary admin account, I would be happy to take a closer look and ensure these tables are correct and that they are loading correctly?
I look forward to hearing back from you and getting this issue resolved.