Smeg S750 Washer doesn't spin thoroughly?

My Smeg S750 Washing machine does not spin thoroughly on any cycle. Maybe 1 in 3 was cycles gets the full spin and clothes come out ready to hang, but mostly they come out dripping wet. I have even tried the Fuzzy setting for spin only, and it only spins about 1/2 speed or less. I thought maybe a loose belt, but the towels which are heaviest came out OK. Also a smaller load seems to slump to one side and cause machine to go out of balance and into error. I hate this machine. Please help before I set fire to it.