St. Augustine was a bishop. Does Calvinism have bishops?
St. Augustine said the Mass. Do Calvinists say Mass?
St. Augustine observed the feasts of the martyrs. Do Calvinists observe the feasts of the martyrs?
St. Augustine was a monk and wrote a monastic rule. Do Calvinists have monks?
St. Augustine gave instructions and advice to nuns in Hippo Regius. Do Calvinists have nuns?
You call yourself Augustinian while simultaneously repudiating Augustine's entire life?
All of these objections are a combination of ignorant and superficial, and consequently not really worth addressing one by one. Superficial in that, a Bishop who believes in the doctrines of grace that animated Luther and Calvin and all the great reformers is not a Roman Catholic who can condemn Luther, but a Christian on par with Luther, whatever outward pomp he wears or mode of religious practice.
I have long noticed that Catholics are often hung up on appearance, but don't care about the actual doctrines of salvation. They would rather debate you on something irrelevant and worthless, but not on the meaning of scripture, faith, justification, and grace.