Secure My Gmail Now!

I'm currently facing a pressing issue where my Gmail account is being used unauthorizedly to send out marketing emails. My primary objective is to regain exclusive control of this email account and ensure no further unauthorized access occurs. Given the circumstances, I'm not certain about the intricacies involved, including whether SMTP is part of the problem, nor have I made any attempts to rectify the situation thus far, due to a lack of understanding on how to proceed effectively.

**Ideal Skills and Experience:**
- Proficient in Gmail account security
- Experienced in identifying and rectifying email account compromises
- Knowledgeable about SMTP and how it could be exploited
- Skilled in implementing robust email security measures, including but not limited to two-factor authentication

**Key Requirements:**
- **Immediate Account Recovery:** Assist in swiftly regaining control over the compromised Gmail account.
- **Diagnosis:** Conduct a thorough investigation to determine how the account was compromised, with a suspicion towards SMTP vulnerabilities.
- **Preventive Measures:** Advice and implement state-of-the-art security measures to prevent future incidents. This includes guiding through the process of enabling two-factor authentication and reviewing account recovery options to secure the account further.

I'm in urgent need of an expert who can navigate through this crisis efficiently, ensuring that my Gmail account is secured and that such incidents are averted in the future. Your expertise in email security will be invaluable in restoring my peace of mind and confidence in using my email account without fear of unauthorized usage.