Reviews of Ngai Heng Battery Co - Singapore

I must share my experience at this Ngai Heng along Yio Chu Kang road with all. I just drove out of their shop very agitated. Changed my car battery at their shop in March 2015. Can't start car due to batt once in Dec. Went back to shop and he say must charge the battery. He never tell me there's a charge and just go ahead to do it. After all is done he say must pay $8. Ok, he's done his work and $8 is a small amount so I just pay, thank him and left. Can't start car again in end Jan. I told him this is the 2nd time and since it's under warranty can I get a one to one exchange. He say must bring back to manufacturer to check. I agree and he took out and just put in an old looking batt into my car. 2 wks later he called and say the batt got prob so he'll give me a new one so he ask me to go down. I went down and was shocked to hear him say there's no stock for this brand and he'll replace it with some other brands. I would prefer to have it replaced with the same value battery naturally and say I want the same brand. He uttered : so troublesome (in mandarin) and say stocks will only be in in April, which is 3 months away?? Ok, I accept it (what to do?) and drove away. One month pass and I was thinking what if 3 months later he say no such things and he don't owe me a batt? So I went to his shop and asked him to write me a note or something to say that he owed me a batt. He say 'No need to write lah so Troublesome'. I say uncle this is for both good in case u forgot abt it months later. He say I 'Talk anyhow （你乱乱讲话). All these while I've been talking to him politely with a smile but after he said that I started being firm to him. Anyway managed to get him to write a note on my note pad. Now is already end March, stocks not in yet. I'm starting to worry that the old looking batt will go flat soon. Went to the shop told him I'll accept the replacement. After installing in the new batt know what he said??? He asked for $20 installation fees!!! Said he told me that. That was not mentioned to me at all b4 hand. I firmly refused to pay. This is a sly old man. His name is Mr Ngai and he's the boss. Buy with him at your own risk.