Well, it depends on your view of 'disaster'. It does exist, but the only one I can think of is Ratners the jewellers, whose shops vanished like snow on a summer's day when Mr Ratner said on record that a couple of the lines they sold were crap. The rest of the group (e.g. H Samuel) was unaffected. VW took a hit over emissionsgate but are still with us - both of these examples involving customers who were, or could be, personally affected. Boycotts by customers not personally affected are rarer, I think, but Liverpool boycotting The Sun (also still with us) is one such:
https://www.bbc.co.uk/news/uk-england-merseyside-60040090.