Hi all I am looking for some advice. 
I cancelled my sim only contract (I was out of the minimum term) as I could not get a cheaper deal and was too expensive to continue.  I cancelled over the phone.
I have a default for non payment (£57) on my credit file.  These are payments for the 2 months after I ended the contract - so would not have been payments I needed to make.  There was no cancellation period and the services ended to my sim. 
I have had very difficult personal circumstances and the discovery of this has been extremely upsetting in a time I am trying to get my personal life in order.  
Any advice?
I am also going to add a post in the tv service forum for the same issue ☹️😢