Walls and Ceilings - Suspended/drop ceiling question

I have a suspended ceiling in my kitchen, the house is 35 years old. The ceiling grid is 36 inches by 36 inches. Two fluorescent light fixtures are mounted on the unfinished ceiling above and there are four (4) 36 x 36 inch light panels/ diffuser in the grid that let the light in to the room. One of the light panels cracked and I am trying to find replacements. Due to the odd size 36x36 I cannot seem to find any, does anyone have any suggestions or sources?

I’m not looking to replace the ceiling at this moment if I can avoid it.

Thanks

I would try a specialty lighting store or electrical supply house. They should be able to order them for you.

Wow, that's a big grid. Out of curiosity, what type panels do you have? Are they standard material, or custom made? You will need to get a specialty store to cut the larger diffuser, as the largest one I have seen is 23 inches on any given side.