I am a Sri Lankan. While in University in the UK I had obtained 2 phones on a pay monthly scheme. I returned home a month before my Visa expired knowing that my monthly payments would be defaulted and that I could do nothing about it. I had never checked my credit file while in the UK or after, so I am unaware if any CCJs have been directed at me or what the ramifications for my defaults are. Now I am employed and advancing and may have to visit UK again sooner or later, either as a tourist or as a representative of an organization.
As immigration laws in the UK and around the world are always changing, you may wish to query this with who would be sponsoring you for a Visa, or who is assisting you in preparing the forms.
Currently to my knowledge, having left debts in the UK does not impact the majority of Visa’s to enter the country. For citizenship in the UK, there is a good character section, but having or leaving debts behind in the UK is debatable as to if this impacts one’s good character.
Leaving unpaid accounts or debts in the UK, in themselves, is not a reason to be refused entry. So no worries there.
If you want to try and settle or pay off the accounts, you can simply contact the companies in question, and inquire as to the balance and paying them off.
When did you leave the UK? How much in total are we discussing?
I ask as the accounts may have been passed on to a collection agency, in which you could contact them to inquire about settling the accounts or making payments.
For some jobs and positions, credit checks can be done by an employer. As to if these unpaid accounts would cause an issue I cannot say, you could always get a copy of your credit history and see how the accounts may or may not have been reported.