Predilection with “get” or “got”

Some people of a certain generation and background (like me) can recall being told at school NEVER to use this so-called "ugly" (ie lower-class) word.
Quite why the word "get" was deemed bad was never explained, and that indeed is the question.
'Get' has been in English an awful long time and is widely used:

etymonline.com/index.php?allowed_in_frame=0&search=get

Nonetheless, for examinations/academic writing I do still teach my students to consider using a more precise word such as "obtain/receive/become", if only to demonstrate a wider lexis.

However there are phrases where "get" is the only natural choice:
"They became married" would sound quite odd.

I would suggest there is little wrong with sentences like "The hard disk got erased by mistake" either, where get=become befits the situation.

As to why "people" use "get" so widely, well I think it might have something to do with it being somehow harder to formulate the sentence without "get" in some situations. But who are these people? Be not peeved, life is too short.

"Get" is doing some interesting work here: it's an active verb doing something rather similar to the copula, "to be," in that it implies the initiation of a state of being. This lets you produce a kind of makeshift subjunctive or future tense to refer to a state of being that hasn't started yet ("don't get upset!") without using the more cumbersome "become" ("don't become upset!").

In your example, "If he contacts you" is indeed better, because it is an active and not a pseudo-passive construction and thus more direct. (It's also less informal.) But this is no surprise: people rarely think in a straight line from A to B!