Of course you should be careful not to jump to hasty and inaccurate conclusions. Yet it is often not immediately clear if you have actually been ‘ripped off’ and unfairly cheated/treated OR have been given ‘the run-around’ about this or other matters. In the long-run you need to avoid getting into such situations where possible, to recognise some typical signs, and to generally practice a balanced or open-minded skepticism about other people and their claims/offers.
In the short-term, you can learn some useful tactics to speed up the process of becoming reasonably certain you have been treated with ‘bad faith’. Since ‘the run-around’ is often a secondary sign of having being treated unfairly, a key is to calmly insist on further clarification through basic questions which can link both a general situation and particular details (see related links below). After this you should institute action to ensure that if the information is not forthcoming you will at least clearly establish that fact (i.e. most people will be concerned when an initial verbal query or complaint is put on formal record).
Any further efforts of ‘keen engagement’ will likely unsettle even the most recalcitrant crook or bureaucrat. There will be various signs such as a general shiftiness or failure to keep eye contact which will tend to remove any residual doubts. In short (as we have long observed in practice) people will tend to ‘hang themselves’ (or not – if they are genuine) when confronted reasonably yet persistently.