As a rule you will not be contacted by the relevant trademark registering office. What happens is that the registration filing is published, and if you are opposed to it going through you will need to file opposition within a certain period after the publication.
That's why organisations with IP to protect typically directly or indirectly (that is via counsel) use trademark watching services. Essentially these scan the where ever the filings are published, and will send you alerts or whatever when something turns up on the radar.
Actually filing opposition is rather tedious and expensive, and particularly when different good/service classes are being used, sometimes difficult to actually be successful with.