I can understand your frustration and disappointment.

Zoysia is difficult to establish from seed. While poor seed quality may indeed be a factor, there are other potential issues. Proper moisture is critical. You said you watered and also relied on rain. Zoysia seed requires consistent moisture to germinate; it can get be too soggy or the seed will rot, but it also can’t be allowed to dry out. Young sprouts will die if they start to sprout and then are allowed to dry out, so getting the right moisture level can be tricky. Other common mistakes are planting too much seed. Crowding can lower germination rates.

Assuming you did everything correctly, poor seed may have been the factor. It would be worth contacting SuperSod to find out if others also had issues with your particular seed lot.

Unfortunately, we are not permitted to recommend specific businesses. I would suggest an internet search to find those that are recommended. I can however suggest a possible way to get an economical zoysia lawn, and that is to plant plugs instead of putting out sod.

The following information comes from this link: https://caldwell.ces.ncsu.edu/2018/03/lawn-care-questions/

“One square foot of sod can provide up to 500 sprigs or 36 two inch plugs. A plug is a round or square piece of sod, usually 2 to 4 inches in diameter with a core about 2 to 2 1/2 inches in depth. The term “sprig” applies to a complete vegetative portion of the grass plant. A sprig should include leaves, a stolon (runner), and some roots.

When plugging, place plugs 2 1/2 inches in diameter (larger than 2 inches best) at 8 to 12-inch intervals. Press plugs into a similar size hole to obtain good soil contact. Do not plant the plugs too deep or allow the plugs stick up above ground level.

When sprigging a new lawn, don’t plant into an existing lawn. Sprigs should be planted in a prepared weed-free plant bed. Sprigs are obtained by tearing apart a piece of sod. Each sprig should be at least 3 inches long and contain one or two nodes. Sprigs are planted with one end below the soil and the other end (with leaf shoots) above the soil. Fresh sprigs are planted 4 to 12 inches apart in rows, and 8 to 12 inches between rows.

Zoysiagrass plugs or sprigs are best planted early in the growing season from late April through June. Later plantings may not become established before winter.”

Maintaining a zoysiagrass lawn is different than maintaining a tall fescue lawn. For information on proper care see https://content.ces.ncsu.edu/zoysiagrass-lawn-maintenance-calendar

Good luck!