Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: Energy giant Scottish Power is mired in disputes and struggling to clear a giant complaints backlog — six months after it promised to clean up its act. Money Mail’s postbag is still overflowing with letters from angry readers, despite the company’s vow to change its ways after scooping our Wooden Spoon award for rotten customer service. In January, after the power firm scooped our ‘gong’, boss Neil Clitheroe promised an overhaul, blaming its problems on a botched £200 million computer upgrade. The firm had been under siege from irate customers for much of last year. We handed a dossier to Scottish Power as complaints poured in and alerted regulator Ofgem last summer.Angry readers are still receiving rotten serviceScottish Power received more complaints than eight rival energy firms combinedBoss Neil Clitheroe says firm is on track to clear issues by end of the year 
 Question:The 71-year-old retired flooring contractor, from Troon, South Ayrshire, was sent a letter in December to say his _ account was £759 in credit.

Scottish Power