Credit default on file

I have tried to apply for a mortgage. Just ran a credit check and seen i have a credit default on my file name for virgin media from when i had WIFI.

This doesn't make sense i never received any letters for a final bill or anything etc. i had always paid my bill via direct debit and it was automatically taken and never had any issues. virgin media cancelled the direct debit through the switch so it was not like i switched it early myself ? 

i think the account is paid up in full anyway and this default was put on by error. even if it is not i have never received any notice that i was going to be put on default ? I really just want this default removed off my name as it has had a major effect on my life now.

i am still a virgin customer and have 2 lines which are being paid through direct debit.

I appreciate i may sound frantic but this is having such a major impact on my life, and it is upsetting because i have been a loyal customer and still am a customer and have always recommeded virgin.

as shown below i fnished and settled in january when i switched over.