You are at risk of losing both your payments and your flights. If you have been given flight numbers contact the airline to see if it has your name, and if so, which ATOL company booked it. Details of ATOL companies can be checked here. Retail agents rarely deal with airlines directly; they deal with ATOL holders who in turn deal with the airlines. If the agent is a member of a trade association you should also contact them for advice. You should also contact ATOL Enforcement.