I have been a dog boarder/day carer/walker for past 8 years. Due to health issues I'm having to stop. Have given all my clients notice. Every client I've ever had has always paid me on time, usually before I've even sent the invoice, except one. They have never paid me the full amount each month, only a portion of it. I know they've had issues so have always tried to cut them slack. They now owe me nearly £1000, money I can't afford to lose, and despite me sending monthly invoices throughout detailing all the dates ive had their dog, and even my spreadsheet, they are now saying they don't think they owe me that much. They are also giving me all kinds of reasons why they haven't paid me yet (life circumstances, illness etc) despite me sending the final invoice in May. I've even offered them a payment plan but now they aren't replying to me. I know they've got stuff going on so don't want to be a nag but I need that money and I've earned that money!! I'm thinking ultimately I'll have to go to small claims court but would prefer to try and resolve this amicably if I can. What would you do now?