Perhaps you could argue your situation, having a young child, smelly wet floor and the 12th just not being acceptable and if they would allow for another qualified engineer of your choosing to come out and they reimburse you?
The 12th clearly is just not good enough, I'm sure you dont live on a deserted island somewhere
Complain complain complain, ask to talk to a mangager blah blah blah
tel lthem you have 2 young kids, one who needs clean bedding most days due to her skin condition (who cares if its stretching the truth a bit) and your other daughter is in washable nappies. the 12th isnt acceptable.