Can you help me?

Sure, why don’t you use a custom form then, override the template (contact.php) in your Child theme, then remove the code that shows the form and within the content (when editing the page) add your custom contact form 7 form.

As for your spam, make sure you enable the spam filters at your hosting.

Could you please guide me how can I do it? Will it retain the current style of the form?

1. Create your form.
2. Duplicate the contact.php file and place it inside your Child theme directory.
3. Edit the new contact.php file and remove this bit:

<?php if(isset($hasError)) { //If errors are found ?>
	<div class="warning closable"><?php _e("Please make sure all fields are correctly filled in!", 'Aqua'); ?></div>
<?php } ?>

<?php if(isset($emailSent) && $emailSent == true) { //If email is sent ?>
	<div class="success closable"><?php _e('Your email was successfully sent! Thank you for contacting us!', 'Aqua'); ?></div>
<?php } ?>

<form action="" method="post">
	<p>
		<label for="comment_name"><?php _e('Name', 'Aqua'); ?><span class="required">*</span></label>
		<input id="comment_name" class="aqua_input" name="comment_name" type="text" value="">
	</p>
	<p>	
		<label for="email"><?php _e('Email', 'Aqua'); ?><span class="required">*</span></label> 
		<input id="email" class="aqua_input" name="email" type="text" value="">
	</p>
	<p>	
		<label for="subject"><?php _e('Subject', 'Aqua'); ?><span class="required">*</span></label> 
		<input id="subject" class="aqua_input" name="subject" type="text" value="">
	</p>
	<p>		
		<label for="comment"><?php _e('Message', 'Aqua'); ?><span class="required">*</span></label>
		<textarea id="comment" rows="8" class="aqua_input" name="comment"></textarea>
	</p>
	<p class="form-submit">
		<input name="submit" type="submit" id="submit" value="<?php _e('Send', 'Aqua'); ?>" class="sm_button">
	</p>						
</form>		

4. Place the shortcode of the form you created in the page.