Greetings of the day.
As per the information provided by you, I wish to tell you, that merely replying to the objections of the registrar does not give you the trademark. Even after the registrar accepts and publishes the trademark in the journal, there is still the threshold of the opportunity given to the other parties to object to the trademark, if it infringes their registered trademark.
With regards to your first query, well, if you don’t attend the show-cause hearing, your trademark application would be considered as abandoned, meaning that you cannot pursue the trademark further and the trademark would be open for any other entity to use. With regards to your second query, there would be no other action upon you if you do not attend the show-cause hearing. Generally, no personal action is taken by the registrar in such cases, but if the party fails to attend to the hearing despite repeated notices and without any due cause, the Registrar may impose some costs on the applicant.
So, my advice would be that you attend the show-cause hearing and convince the Registrar to give you the trademark. Otherwise, the reply you sent earlier would be an attempt in vain.