[Avodah] bad service

[saul newman]

http://jewishworker.blogspot.co.uk/2013/07/what-does-this-ad-from-egged-say-about.html
(or <http://j.mp/10PeqEm> -mi)

and response
http://jewishworker.blogspot.com/2013/07/the-charedi-response-to-eggeds-ad-about.html
(or <http://j.mp/12pjIHL> -mi)

when, if ever, does 'bad service' allow one to not pay [some or all].
eg while one may elect not to tip the waiter , one still has to pay for
the dinner....

is there some relation to ona'ah , or if one contracts for a product [in
this case delivery from point A to B] the quality/temperature/rudeness of
the ride are not part of the equation.....