Turns out, they indeed had answered within a week and my mail provider had apparently decided, that I don't want to recieve some emails already before my inbox limit was fully reached.
I sent them an inquiry recently and they answered within nine days. So I guess if anyone doesn't get an answer for more than two weeks, they should just try again.
Also my phone was already repaired in July, so they were almost right with their initial projection of how long the repair process would take. Only took one month longer, which is kinda good for their standards :D