Hyundai Poor Service/Quality

Hi. I am experiencing an unpleasant service from Hyundai. My H1 bus needed repairs in 2017 which ultimately led to engine replacement at the cost of 109k paid for by the warranty. This was completed in April 2017. This year now In April/May engine problems resurfaced and a different Hyundai service centre now also wants to replace engine. How can an engine that was supposedly new in 2017 now require replacement 12moths later. The warranty expired shortly after the engine was replaced . Now i am informed that the new engine has no warranty whatsoever because of that. I feel really hard done by this company. Hole to get some ideas on how to deal with this issue.