You have to be the most annoying, persistent, irritating, naggy person ever. Or it won’t get done. The ones who nag and moan and nag and moan, get attention. Don’t be rude or nasty, be nice about it, but do go on and on and on. Be at the Customer care every time you can, “ well I spoke to so and so like you said, but I’m getting the brush off, I want this fixed as poss, can you send them an email for me please, can you phone them now please, can you give me another person higher up to talk to please.” Pester the site manager again and again and again in the same way.
I say my ex boyfriend’s mum do this, it was almost embarrassing- she knew every builder by name in the end. She was a mixture of wheedling, hilarious, friendly and annoying, she got loads of freebies too, “oh, it’s such a shame there isn’t a cupboard here, but we don’t have any matching doors but I thought I saw some spare in that skip can I have the, is there anything else like that going spare? Can I have first refusal?... “ they gave her loads of freebies and extras! And every item on the snagging list was either resolved or haggled for a free upgrade or fix somewhere else in the house or garden.