Woolworths online shopping

Woolworths has some very good products. They offer an online shopping and delivery service. We have used this service a number of times in the recent past. Although it has a good look, it falls short in a number of respects. Orders cannot easily be changed or modified after they have been placed. We phoned and asked whether this could be done. We followed the directions given, and ended up paying twice. Getting through to their call centre was not a good experience, we held on for 2 hours. We sent numerous emails, which were responded to days after sending. Eventually we received a refund. The online ordering and delivery service should only be used by those who are 100% sure about what they are ordering. Or, Woolworths could attend to the shortcomings?