Sometimes wood chips and bark would be in the soil if it is Triple Mix. But if it is only topsoil it should be clean of anything including weeds.

Topsoil is so variable, I do a soil analysis first, then
buy it. Just put some in a jar, shake it up, and watch it settle out. It sounds like you've been had, but I wouldn't be upset about it, I'd just call them up and tell them you changed your mind about buying it, and that you'd like your money back, and for them to come and take it away. Cheers.