It is a given with spiders and spider based morphs. They all have a wobble some more than others. The breeder is not blameless however shipping a snake with mites is poor practice at best, and also selling a spider based animal with a magor wobble the customer should have been informed before the purchase.

As per mites there are chemical treatments (P-A-M) but if you do not have any don't wait fot it keep up the soapy water soak (a little soap not lots mild hand soap) everyday and before the snake returns to its enclosure The enclosure must by scrubbed spot less (bleach 10%) and boiling water in the enclosure as well every day! Before the soaked snake is returned. The same for the area surrounding the enclosure it too must be cleaned as well, everyday. The adult mites leave to lay eggs the can travel farther than you think and they like damp dark areas so keep things drier than normal and scrub into the corners of everything.