pop up sink plug

My house is completely fitted with click-clack wastes and they've started to fail in various ways. In theory you can unscrew the piston section for maintenance but mine are solidly stuck to the waste itself and when I try to turn them, the whole waste starts to rotate as well. I can't use too...

After unblocking the bathroom sink (long story) it appears that whilst unscrewing the pop-up plug, the bracket holding it in place had snapped off. Please see photos below. What options do I have to replace or fix this issue? Are we talking about a brand new sink?? :eek: I know getting a...