They had hoped to double their exposure to possible clients by showing off outdoor accessories at the first Solex on 6-8 July, as well as at September's Glee.
But repeated requests to book stands have fallen on deaf ears with organiser the Leisure & Outdoor Furniture Association (LOFA).
Director Simon Gregory of Kingsford Barbecues, of Stroud, said: "We have been trying for nine months to get a space. It's frustrating and we'll have to go full-tilt at Glee."
LOFA secretary Richard Plowman said: "We sold all our space last November and should have got back to people."