According to the food-and-drinks maker and one of its executives with knowledge of the deal, PepsiCo was using only 36 of Teslas promised 100 electric trucks as of this month.

The shortfall, which hasn’t been previously disclosed, lays bare the challenges for Tesla as it seeks to become a high-volume player in the truck-manufacturing business. Other would-be Tesla customers including food distributor Sysco, UPS, and Walmart Canada continue to wait for Tesla Semi trucks and are turning to rival electric-truck makers.

The struggles of shipping enough Semis come at a bad time for Tesla, which has seen growth for its consumer electric vehicles slow, forcing it to cut prices and hurt margins. In addition, Reuters reported this month that Tesla had decided to cancel its long-promised inexpensive car that investors had hoped would drive further growth.