Where can I get my controller fixed

You can visit xbox support for more information on repairs.
https://support.xbox.com/

The warranty period of the device can be checked on the following website
https://account.microsoft.com/devices/

If you need to exchange equipment you can do so on the following website
https://support.xbox.com/help/hardware-network/warranty-service/getting-your-product-serviced

In the meantime, you can contact Microsoft Customer Service at
https://support.microsoft.com/contactus

Hi there,

please see this link for the steps on how to get your controller fixed/replaced at the 'Accessory replacement' section here:

https://support.xbox.com/my-account/warranty-and-service/getting-your-product-serviced

which states:

If you purchased a Microsoft Xbox accessory within the last 30 days, you can return it to the retailer with your original proof of purchase. If you purchased the accessory more than 30 days ago but within the accessory warranty period, you can order
a replacement accessory from
Device repair (console registration is required). Make sure you click
Replace an accessory instead of “Repair my device.” Follow the onscreen prompts to place an order.

I'm sorry you where unlucky with controllers. If they are under warranty you can get them fixed.

Hello Scrima,

Thanks for reaching out to the forums. We understand you have a question on replacement. If you already filled out a replacement request, all you need to do is follow the a steps of the email you received. You will need to mail the controller out. So check
your email that you used to set up the replacement.

Thanks,

Brad

For support on accessories:
https://support.microsoft.com/en-us/devices

i wanna know if i can do it my self

We cannot give you tips in tampering with the accessories