If Chen and his associates claim that the lack of fossils is anything other than a problem of the fossil record then the evidence is against them. The discovery of phsophatised organisms from the period preceding the "explosion", which indicate that the diversification had started well before is strong evidence for that.
To explain, phosphatisation is a rare form of fossilisation that is only good for preserving very small organisms. The more usual forms of fossilisation only preserve considerably larger forms. Thus it appears that the early diversification involved organisms too small to be represented in much of the fossil record.
You are also wrong about the production of phyla. By the very nature of taxonomy we should expect to see phyla appearing early. Even Linnean taxonomy was based on modern organisms and if the divisions seen are the product of evolution then the most basic divisions should appear early on. It is not that the animals of the Cambrian explosion were so radically different that they would automatically be classified in different phyla if we made no reference to modern life - it is that the differences between them are important to the classification of modern life.
More importantly you misrepresent Chen in one crucial respect. He claims that currently accepted theories of evolution cannot explain his observations - but HIS theories can. He is not attacking evolution, he is promoting his own views.