Sounds like they may have replaced the LCD connector and not soldered the pins properly; meaning the connector is making some connection with the board when moved, but otherwise is not making a permanent connection to the board. This is something I have done before when I started off, but luckily picked up on before sending it.
Contact the repairer. If they are offering a warranty, that should cover the whole board since this has had liquid spilt across the WHOLE board; you have paid them for logic board repair, hence if it isn't working, they haven't done their job. If it is an issue with the board that wasn't picked up on by them, any decent repairer would cover this. They shouldn't cover something under warranty if it is a part unrelated to the logic board, or it is a manufacturing fault (for example, GPU issue on 2011 15" models).
Contact them and take it from there