Friendly speaking while using the TinyMCE editor in wordpress this one is the issue it from go to visual to text its removing those tags
for overcome those issues do not remove formatting just use this way
Write your <p> tags like this:
To prevent that, br tags can be written like this:
<br class="blank" />
We are glad that you preferred to contact us. Please fill our short form and one of our friendly team members will contact you back.