Older Shimano brakes are a pain to bleed without the correct, and now hard to find tools, however a good LBS should have those tools. From your description, it's nothing to do with any bolts, as the caliper would be noticeable loose if these were not done up, more the bleed itself, as mentioned, on older Shimano brakes, this is a pain, and much more difficult than the current ones to get right first time, which is the norm with current Shimano brakes

For the bill, any significant change should have been advised/authorized by the customer (yourself) before proceeding, as with that difference, you could have got a new set of brakes, eliminating the issues you currently seem to be having.

Would ask the shop to have another go at the brakes (FOC) as they seem to have failed to fix them in the first place, and then look for another (and better) LBS for future work