I had facial fillers done by an experienced dentist at a cost of £350
They have caused 6 weeks of issues, 5 visits to A and E, drainage at A and E, 6 courses of antibiotics as the infection raged all over my face, prevented me from
Working, taken multiple days off, I have thrush in every orifice
, they have had me postpone major surgery as the infection would not come under control
And now they want to charge me the same amount to dissolve it 
They have accepted it's a rare bacteria caused by the fillers that the antibiotics can't get to
Is this in any way reasonable?
What would anyone else do?