If the time limit for trademark objection defense is missed, you will lose the opportunity to refute the other party's objection, but it does not mean that your trademark is invalid. Whether it is valid or invalid will not be determined until the Trademark Office has reviewed the objection;
If you miss the deadline for reply and don't reply, the Trademark Office will still go through the procedure of trademark objection trial normally, but you can't see your reasons and evidence during the trial, only your own reasons and evidence. He will make a ruling on your trademark according to the materials of objection and what he knows. If the other party has sufficient reasons and complete materials and you don't reply, then the Trademark Office may listen to their opinions and make a ruling against you. However, if the other party's reasons are far-fetched and the materials are insufficient, then the Trademark Office may not support their objections and make a favorable result for you.
So, don't worry too much. Since the deadline for reply has been missed, just wait for the result from the Trademark Office, which may not necessarily support the other party's objection.
However, since you didn't reply, it's not good for you. Therefore, you should make plans in case the trademark doesn't come down, and don't catch yourself off guard at that time. The period of trademark objection is relatively long, and it usually takes 2-3 years to get the result. You can still use your trademark normally now, and you should also make preparations for the next step at this stage.
We are a professional trademark agency under the Trademark Office. If you still need advice or help, you can call me at Baidu HI at any time.