Eureka Forbes — Water quality after service has gone bad

After the filter was replaced, there was an issue with the water heating up. when the service technician came he changed one of the filters again for what ever reason. it did not look like a new one and now the water tastes salty. i called for service and the tech did not check anything. just checked the tds and told this is the best they can do. for 1 year before the service the water tasted good and now all of a sudden it is bad. if i call for service again ima scared the same guy will come and tell all is ok.