My ipad mini 6th generation was stolen and erased, i have the serial number but whoever has it deleted my icloud off so i cannot track in

A lost or stolen iPad cannot be traced or located via its Serial Number or other identifiers.

Start here:

Locate a device in Find My on iPad - Apple Support

Here is Apple’s advice for lost or stolen devices:

If your iPhone, iPad or iPod touch is lost or stolen – Apple Support

Use the Find My app to locate a lost or stolen device – Apple Support

If the Find My iPad feature was enabled prior to it being “misplaced”, then if active, you would stand a good chance of locating it. 

However, if the feature was not activated prior to being misplaced - or the iPad has been inactive for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover the iPad may have been lost.

eriana243 wrote:

Is there a way to track it by the serial number?

No, can't be tracked by serial or imei number.

Yes, unless you have a non-Apple insurance policy which says otherwise. Apple doesn't cover lost or stolen iPads.

(241130)

eriana243 wrote:

Will i have to pay for a replacement even if i have apple care?

Contact Apple care and see what they say?