I have just bought a condo (townhouse) in Edmonton. I have found many problems wrong with the place, from plumbing to sewer clogs to lack of insulation to mold found in the basement when I went to remodel. What can I get the previous owners to pay for? Can I just give them there place back? I have been in here just over a month.

No you can not "just give them the place back"
Did you have a home inspection done, sounds like they may have done a poor job?
Was the mold visible before you tore out a wall, was there any way for the previous owner to know.

Also if the place sat empty for a while, plumbing and sewer issues are to be expected.

I did have a home inspection, to find the clog in the kitchen sink you would have had to run the water straight for 3 minutes, we ran it for about 1 minute. The piece of wood in the sewer behind the washing machine we would have to run the washing machine to the spin cycle to see the overflow of water that goes into the sink beside the washing machine. The mold was hidden behind there belongings in the room. Yes they know about the mold, when they came to pick up there mail at a later date my son mentioned to them the mold and he said he knew but never had any problem with it. ITS MOLD, ITS DANGEROUS.

... he knew but never had any problem with it. ITS MOLD, ITS DANGEROUS.

No, not all mold is dangerous.

I did have the mold tested and its not a black mold. I am just so frustrated. I appreciate your comments. Thank you