I would try and get a refund for it when you get something else
The Hamster Heaven doesn't look quite so awesome when you take all the plastic tubes, shelves and penthouse out lol! They just make it look fun and colourful. Without them it looks a bit like the Alaska! So you can buy fun colourful toys and make the Alaska look fun too (or make toys). A lot of people end up removing the tubes from the Hamster Heaven anyway as hammies can block them up and they're a bit of an escape risk too. Our hamster is quite large and got stuck in tubes so I think you're right to not risk that if your hammy is quite large. Rat sized toys and tubes are best for hamsters really.
This is my old cage - the Savic Mickey 2XL it's exactly the same size as the Savic Hamster Heaven but comes more or less empty, and I just put my own bits and pieces in for our large syrian. This size is good for most Syrians - although does limit what you can fit in once you have a wheel, a house and some toys. And as you can see it was quite full!
The big pink thing is a rat sputnik - bigger than the one that comes with the Hamster Heaven but I also used the smaller one as well just to put his veggies in as it was a bit small for a syrian to sit in. The stripey tube is just a rat cardboard boredom breaker tube tied up with sisal string.