I am using ZenCart 1.3.7, my hosting company isntalled the NoChex mod last April

It had been working very well until the beginnig of new year. Recently a problem happened frequently: soem custoemr paid for their order successfully, but noChex didn't notify us about the sucecssful payment. As a result, we don't know there is an order from our customer, and our customer still have the goods in their shopping basket

We have contacted NoChex. They asked us for the following:

Call Back URL
Cancel URL
Success URL

Based on the version of ZenCart we are using (1.3.7), can anyone tell us what values we should provide? Please assuem our shop are:

http://www.somehost.com/shop/

Many thanks