i am a self employed bricklayer working in the west midlands. i have just completed pointing a house and the customers appeared happy with the work. they requested a invoice and also bank details to pay the balance into my account. 5 days down the line and nothing paid in, so i contacted the customers and they requested a guarantee of my work. the question to all is, i do not advertise the fact that i guarantee work (and they did not request it when i gave them my quote) i did mention and present to them that i am a member of the guild of master craftsmen and that i have public liability insurance and that was all. what is my next please?