Kingsley-Ann, owner of Kingston Stones, a bespoke jewellery store, tells you that at the start and end of the month of December, customers owed her GBP 5,490 and GBP 6,900 respectively. She also advised that some of them returned goods totalling GBP 2,700, and she refunded one customer GBP 250. Additionally, she advised that due to the Covid-19 impact on the world economy she had to write-off bad debts of GBP 1,160. Finally, she says she sold jewellery for cash totalling GBP 8,950 during the month. What is Kingston Stone's total sales for the month?