Your and the repairers obligations are whatever you agreed in your contract subject to any consumer protection law.
"But I don't have a contract" I hear you say. "Oh, yes you do" I reply. At the very least you have a contract under which they repair (or make their best efforts to repair) your camera and you give them some money. more than likely, there are specific terms of the contract drafted by the repairer which you agreed to, either by signing something or by clicking on something on a web page (you know all that stuff nobody reads? That's a legally binding contract)
So, what does the contract say about time?
If it says nothing then there is an implied term that the repair must be done in a reasonable time. What is a reasonable time? Its the time that a reasonable person who knows all the circumstances would consider neither too short nor too long. Is 2 months a reasonable time? Right now we don't have the information to say: it probably is a reasonable time if parts were required to be sourced etc. 2 years would definitely be unreasonable, 2 months? [shrug].
If it is an unreasonable time you can sue for damages (i.e. whatever the absence of your camera has cost you) or seek a court order forcing them to complete the contract by a certain date. In general, time is not a basis to cancel a contract unless the delay is so long that it can be argued that the repairer has repudiated the contract i.e. has no intention of completing it.
However, before doing that, call them and tell them that you don't want to be jerked around anymore and when will you be getting your damn camera and see what they say.
