ST notice reply thru email

They gave you email id
if yes no problem you can send
if no better to send

I have send my reply and supporting documents thru to the email address Mentioned in there letter head during lockdown and specifically it is not mentioned to reply using the email and I had called their office during that time to query about it and I had no resources reaching personally to the office for submission due to lockdown and no one had answered the phone call. but now again they have send me show cause notice that I have not replied to the notice intentionally and they say they have send several other reminders which is false and I have not received further notice or reminders or phone calls or emails in this regards, I just received the first query notice letter and now a show cause notice. in which now they have charged me with many long list of violations and to levy heavy penalty in regards to not replying to the first notice and additional assessment of other years which was not mentioned in the previous first notice. I have rechecked accurately the email id address as it is mentioned on their letterhead. that I have send it to the right email address and it is perfectly right. please advise