The Reputation Check on Carphone found 42 per cent of people do not agree that its staff recommend mobile phone deals on the basis of customer need, believing their motivation is sales commission.
The poll of 1,106 UK adults was undertaken last week by Opinion Matters.
Just under a quarter thought Carphone offered impartial advice.
The firm split with Vodafone at the beginning of the month after refusing to guarantee a monthly sales target, arguing that such a deal would have gone against its standing as an independent retailer.
Meanwhile, 55 per cent thought Carphone's buyout of AOL UK was evidence of it ‘trying to do too much too quickly' before solving customer service issues.
Carphone head of comms Vanessa Godsal insisted the company's sales staff always offered impartial advice.