How to repair a Giottos MH-1300 ball head? - Giottos Photography

Slacken (or remove) all the adjustment screws, then apply some thin lubricant to the head, see if that will free it.

Most tripods have a 1/4" thread attached to the centre column, which then screws into the base of the head (some may have a 3/8" thread, but the principle is the same).
Grasp the head firmly in one hand, the shaft firmly in the other, and rotate the head counter clockwise to remove the old head. If it has been in situ for some time, it may be stiff to rotate.
Once you have removed the old head, lubricate the threads on the centre column, then attach the new head, rotating this one clockwise.
If the old head will not unscrew under firm manual pressure, remove the centre column and place in a vice, packing it with wooden battens to protect it. Then attempt to unscrew the head, using a mole grip or similar if necessary.

-If you need to order repair parts for your Giottos MG8240b tripod..., (vs accessories such as camera plates)..., I would suggest that you use the following link to contact the Giottos distributor in your country. They should be able to supply you with parts diagrams, this will allow you to provide them with the info to get your tripod up and running again.
GIOTTOS IND INC
-Hope this helps.
Peter

That's not showing up a valid US model number.

Try here.

You unfortunately can replace the screw; however you can find a new plate at www.tripodquickrelease.com. They carry Giotto quick releases.

Send the tripod to:

Spartan Photo Center
197 east saint john st
Spartanburg SC 29306

Repairs are 425 + parts + return shipping. Just depends upon which parts you will need at this point.

In the USA send it to the Giottos distributor for service. HP Marketing Corp. PO Box 715 16 Chapin Rd. Unit 908 Pine Brook, NJ 07058 800-735-4373
In other countries send it to the local Giottos distributor for that country.

In the USA just call us. 800 735-4373

Call us at 800 735-4373 regarding service on Giottos tripods. The legs are not repairable by the owner and probably not by us. Or you can send it to us at. HP Marketing Corp. PO Box 715 16 Chapin Rd. Unit 908 Pine Brook, NJ 07058 800-735-4373

I had a similar problem with my Giottos carbon fibor monopod, but it was still under warranty so they just replaced it.  I'd still give contacting the company that handles Giottos in the US a note and ask them to take care of it, or if not, a recommendation.  
http://www.hpmarketingcorp.com/warranty.html

There is an email address on this page.  They were quite helpful when I had my problem.  It cost me shipping to send the old one back and I had a new one in under a week from the time I sent if off.