You are correct that the tower on Brooklin Concrete's property has been removed. Apparently the new owner of the property wanted the tower removed. Unfortunately Telus does not have any towers in Brooklin as they use Bell's equipment there. Until Bell either gets a new tower, or a temporary tower in place, there may be issues. Getting a new tower up is not something that will happen overnight. As per the comments from Durham Radio News, customers should be making complaints to their carriers directly. In this case, that would be calling tech support. They can then put a complaint in with Bell.
The only remaining Bell tower is one they share with Rogers located in Brooklin Memorial Park.