OP
Octopus
Ouch, what a mess.
So in summary, the kitchen company got you to do some electrics, are washing their hands of the issue, but didn't do the CIS and haven't paid your invoice from November. The customer had another electrician who did some of the work. You and the other sparky don't know/can't agree on who's fault it is.
Who issued the EIC for the complete kitchen and did the necessary notification? IMHO its that person she should be chasing.
So in summary, the kitchen company got you to do some electrics, are washing their hands of the issue, but didn't do the CIS and haven't paid your invoice from November. The customer had another electrician who did some of the work. You and the other sparky don't know/can't agree on who's fault it is.
Who issued the EIC for the complete kitchen and did the necessary notification? IMHO its that person she should be chasing.