Bought used Kaiser Promask 30/40 - warped base, return?

I'm guessing it's an earlier type with a chipboard base. I paid £150 GBP (roughly $220 US). It's this one http://www.ebay.co.uk/itm/291730800418

What concerns me is the top left corner near the blade that pops out to position the paper is noticeably raised (possibly water damage), which wasn't mentioned in the listing. If adjusting the left blade with lid in the closed position it rubs only near this area, but none of the other blades rub. I'm guessing this raised spot is preventing the lower most blades sitting flush which is needed to hold the paper flat?

I'm new to darkrooms. My inclination is to return for refund, but open to any other thoughts. Seems too much money to get the sander out and hope I can make it perfectly flush.

Many thanks in advance

What was the condition listed as in the advertisement?

That is alot of money to pay for an item that needs repairs. Whats the going price of a new one?

For me?... Id return it and wait for a better deal. No rush, be patient.

I looked and this model has previously sold for £250 used and they're nearly £700 new. That's why £150 was so tempting. In hindsight it seems newer models have metal bases which avoid this issue so I'll know what to look for in future. It was described as "full working order" despite some issues, but to me if the blades don't lay as near as possible flat with the base then it isn't.

The eBay ad does state the there is water damage to the unit. Just doesn't say what the impact of this damage is.

At the moment you are UKP 550 in front. I would be tempted to replace the chipboard base with something cut from
melamine faced MDF. Just depends how the rest of the easel is attached to the base. Is it hidden screws, or glued?

I agree with tokam, it doesn't look like it would be all that difficult to fabricate a new base, or you may even be able to obtain a replacement from Kaiser at reasonable cost. It won't be quite the bargain you started with, but you will still have what you need at a good cost.

Sanding it would destroy the melamine surface and leave you much worse off than it is now.