No, the phone is an aggregate of substances (like copper, silver, various metals, and probably plastic) and artificial forms (all the various parts). It is an accidental unity unlike a human being or a dog which is a substantial unity. It’s like a house which is an artificial form composed of an accidental unity or aggregate of substances such as wood and stone. Wood and stone are substances but the form of the house is not. Wood and stone exist by themselves as wood and stone whether they form parts of a house or not. Your arm which is a part of your body will not exist as an arm if it is cut off from the body. It will undergo a substantial change and decompose into elemental substances or compound substances such as minerals.
I might be conflated the terms. Throw in essence if you’d like too. I think my bigger problem is I’m having trouble seeing how there is an objective “other” outside of mere jumblings of matter.
Aristotle liked to use the example of a marble statue lets say of Socrates. Our intellect can distinguish between what the statue is made out of, i.e, its matter as it were, the marble, and the form of the marble, i.e., a statue of Socrates. Marble can be made into a table, a counter top, many other things which is called the form of the marble. This is actually an example of accidental forms of marble because marble is itself a substance composed of matter and form.
Another simple example would be a potter working with clay. The potter can form a lump of clay into a vase, a plate, a cup, a little statue, many things. The clay is like the matter and the shape it becomes is the form the clay is shaped into. We can easily recognize this. The shapes or forms the clay is shaped into are actually called accidental forms because clay is a substance itself composed of matter and form. But these analogies are used to get an idea of the form/matter distinction. In fact, according to the hylemorphic theory, the essence of matter which is pure potentiality is only known by such analogies and through form. Matter does not exist without form and is only known through form. Matter in itself has no characteristics to identify it by, neither, shape, color, weight, quantity, extention, etc. These characteristics of things are due to forms which are united to the matter and which are, incidentally, accidental forms in contrast to the substantial form which is the first form united to matter and causes it to exist simply.