Do they actually say in the TOS that they will delete them? If they do, do they say immediately? How immediately? Right away or, perhaps, 1 month? Unless specified in contractual documentation, words like "immediately" or "soon" do not have any single definition, which allows them to stretch it without technically being in breach of contract. Not to mention that often times, governments mandate data retention for so-and-so amount of time, so the companies are legally required in such cases to keep the data even if they, miraculously, desire not to.