I am very displeased that you have not enjoyed your staying in Pavia at its best.
As mentioned in the description, the house is located in the city center of Pavia, next to the 2 major Piazzas. This location brings many advantages as well as two disadvantages, which you have highlighted.
Since the apartment is located in such a unique location, not everyone can drive there (which brings to NO traffic noise, kids can run around, and gives you the opportunity to walk around the city being careless about cars and traffic). Said so, I am sorry if you had heavy bags to carry to the apartment, but this issue has been clearly disclosed in the website of the apartment and in the direct email exchanges with you prior to your arrival. For any trouble there are taxis stands around the city that could take you to Casa Mimma. This might be unfriendly to a foreign, but the same regulation applies to any Italian city, specifically, the more touristic the city, the more strict the rule.
Concerning the second disadvantage - the noise, I have to say that I live in the apartment next to Casa Mimma, and I will not deny there is some noise, but nothing that cannot be avoided with a pair of earplugs (as provided). I understand that it might be noisy for a foreigner, and for this reason I am working with an architect to solve this problem. However, the Italian lifestyle and the center of the Italian community revolves around the Piazza, in fact, whenever you visit an Italian city you would walk around the Piazza and take pictures of the building surrounding it (e.g. Piazza san Marco in Venice, Piazza s. Pietro in Rome, Piazza della Signoria in Florence etc.). In addition, our culture is loud sometimes at evenings/night, therefore, anytime you rent an apartment next to the major square, you can have the same problem. This might come as a surprise, but to anyone who has visited Italy at least once, it should be a given.