Fostech echo ak47 trigger - Fostech Echo AK-47 Binary Trigger

Absolute garbage does NOT work I installed it in my century arms wasr 10. Which is a very common ak47. So I figured it would fit like every other aftermarket item I have tried on it. Installation went smoothly then it was time for a function test tried pulling the bolt back and it was really hard and got stuck half way on the pull and won’t pull back fully and is hard to push back forward. Failed all function tests!
I have email optic plant they said they only a supplier of the product and have no knowledge of the items they sell.
I have emailed fostech with the problem it took a week to get a response only response I got was a troubleshooting instructions which all required me to shave/file down the brand new trigger basically destroy it then maybe that will work type of solutions I HIGHLY SUGGEST NOT BUYING THIS PRODUCT WILL WASTE 400$ and get no HELP.!!