You should try a visit to their office. Avoid paying with cash; try paying with a credit card or a check so that you are sure that you have proof of payment.
You can get a free estimate on packing and moving costs in advance. Ask any and all questions you have about the service. A very low-cost move is not necessarily always a wise idea. Be wary of some knockoffs posing as the originals. Always keep an eye on consumer reviews and internet complaints about movers and packers.