Thanks for the review. We inform free users about our current promotions. Many value this as an opportunity to get our Premium service with a good discount. The tab opens once per promotion.
If you do not want to receive this information, you can go to the extension settings and turn on "Don't show promo offers".
As for the speed: yes, currently some free users have slowdowns. We're doing our best to fix this.

Hello. To delete Browsec, please right-click on its icon and click 'Remove Extension'. Then click 'Remove' again to confirm your choice. Please contact us at support@browsec.com if you're still experience any issues.

Hello, we're sorry to hear that. Browsec is a lightweight browser add-on, and it doesn't use your hardware much. We haven't been reported of such behavior before. So please contact us at support@browsec.com or use https://browsec.com/en/contact_us. We will be happy to investigate this case and make it right for you.