Walk Behind Lawn Mowers

Why would my Husqvarna mower drive quit working after only 3 months of usage? I purchase a HU700L on May 13, 2013. After less then 3 months my drive wheels quit working. After less then 3 months I am not a happy Camper! First it would not mulch properly. The dealer said the grass was to wet? After 6 days of SUNSHINE, I again tried to mulch my yard, not good. Left clumps behind the mower every 15-20 feet. Dealer said the grass was too long, so I moved the desk up an inch. After another 6-7 days of SUNSHINE, the machine would again not mulch properly. Bought new blade, Not the feathered blade as is sold on machine but a mulching blade reccomended by dealer. I have to bag the grass as still does not mulch corretly, leaving the clumps. Today my drive quit working and I had to take the machine to the dealer to fix. He says it is probably the belt drive, AFTER 3 MONTHS!!!! They also says there is no warranty and will charge $70.00 per hour to find the problem and fix... After 3 months I am not real happy with my machine. Any comments or answers