Need help regarding a MBP Pre 2008 logic board and battery

i took my 2007 MBP into Compu B in on opera lane, cork city, Ireland as the screen was not working. I got the laptop back, with the logic board replaced, 7 days later and the battery was flat in the shop and did not seem to charge despite standing where the demo machines are, trying to charge my laptop for half an hour i gave up, so i said i'd take it home if there were any problems with it i would get back to them and bring it back. When i got home after half an hour of trying i got the laptop to turn on with the power supply in. instead of showing a charging status in the top left the screen read in brackets (not charging) i called apple support who ran through a few resets and then told me to take it back to compu b in cork which is 30 mile away. when i took it in the Man behind the counter said it was probley the new logic bored and said they'd replace it.10 days later when i went into the shop to see what the story with my mac was the bloke told me the laptop had been sent to the wrong place and i would have to wait while they find it and i was given a Macbook to keep me ticking over in the meantime for course work.i was called 5 days after that by the technician who said there is no way the logic board put in it has affected the battery and i would need a new one. a few days after that the technician called me and said he would go halfs with me on the battery 70euro because of the fact the MBP was lost. since then i have been called saying it was the logic board that was put into it was faulty i am 100% sure that the battery charged the first time it went away to be fixed. i'm not pleased that i have to pay for the incompetence of the technician for either installing the new board wrong at breaking the battery or installing a faulty one which broke the battery i am due to pick up my mac this week with any luck and i would like some advice weather i should pay for this battery please reply me as i would like advice for this