Earlier quoted context omitted.
It's not lying because there is some implicit information in the "we are unable" statement. What is implied in statements like this is that they're unable due to their policies. If not for implications like this, almost every single use of "unable" (or "can't", for that matter) ever in a sentence would be "lying" unless something is against the laws of physics.
I disagree. If you buy a product from me with 30 day warranty and it breaks on day 31 and you contact me, I will not give you a refund because: a) I haven't agreed to do so b) I'm not bound to do so c) I don't think it's warranted in this case. But I'm not "unable" to issue a refund. In another case I may say "hm it's out of warranty but you know what, it really shouldn't have broken like that and you're a good custo…
It could be as simple as "Google management reviewed this app and decided it cuts into the bottom line of some service offered by Google." If the low-level person writing emails is aware of this fact then it would be reasonable to understand why they are unable to share the true motivation for suspension. What is more likely is the low level email writer looks up the account and the reason for suspension listed is, verbatim "Ad fraud - <3 Mgmgt." Then the low-level person would not be stretching the truth at all when they say they are unable to reinstate the account and are unable to provide more information.