Essex Police has released images of three men they would like to speak to in connection with the offences.
The first victim, who is in his 60s, was hit over the head and forced to hand over his card and PIN.
His bag and cash were also stolen and the victim was assaulted, leaving him with a broken leg.
That is one of two separate incidents reported in Southend in November 2018, according to Essex Police.
In the other, a teenager was forced into a car at knife-point, driven around for hours before being taken to a cash point in Grays and having money withdrawn from his account.
He had his phone and wallet stolen and was only released three-and-a-half hours after he was kidnapped.
The stolen cards were later used in Rainham, as well as Shoreditch and Hackney and it is believed the suspects might be from these areas or other parts of London.
In total, more than £1,000 was taken from the victims’ bank accounts.
Police say all lines of enquiry have been exhausted and they are now asking the public for help.
People who recognise the men are asked to call Essex Police on 101 quoting the crime reference numbers 42/172586/18 and 42/173760/18.
Alternatively you can contact Crimestoppers anonymously on 0800 555 111.Tags: Grays, Rainham
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