Elon Musk’s electric-car manufacturer Tesla has reportedly failed to deliver on the majority of its solar roof tiles while also enlisting the help of unpaid volunteers to work in Tesla dealerships as the company attempts to exit “logistics hell.”

Tesla is once again facing product delivery issues — except this time the problem isn’t with its cars. The company’s solar roof tiles, which were announced in 2016, have still yet to be delivered to the majority of its customers. The tiles came in four different styles and essentially acted as miniature solar panels. Theoretically, the tiles sound like a good idea, as did Tesla’s purchase of SolarCity for $2.6 billion — but two years later most of the tiles are nowhere to be seen.

In a Q2 earning’s call from August, Musk stated: “We now have several hundred homes with the Solar Roof on them, and that’s going well. It takes a while to just confirm that the Solar Roof is going to last for 30 years and all the details work out.”

Reuters reports that as of May, only 12 Tesla roof tiles were connected to the grid in Northern California. Tesla did not provide CNBC with an updated figure on how many homes have had the tiles installed, but stated that Musk’s “several hundred homes” comment relates to roofs that are scheduled for installation or repair. Tesla has been accepting $1,000 deposits for the tiles since May 2017, but is nowhere close to mass producing the tiles. Musk has blamed production delays on the need for further testing.

At a shareholder’s meeting in June, Musk stated: “There’s only so much accelerated life testing that you do on a roof. So before we can deploy it to a large number of houses we need to make sure that it’s that all elements of the roof are going to last for at least three decades.” Tesla has said that roof installations will increase near the end of the year into 2019.

In relation to Tela’s cars, CEO Elon Musk noted recently that the company’s issues have shifted from production issues to delivery logistics problems. In response to a customer complaining of the long wait time for their vehicle, Musk apologized via Twitter stating that the company was now in “delivery logistics hell.”