Because it is a way to get money. If you don't open the shop and you don't get any more money, you won't be able to ship anything. If you sell more tablets (with a profit margin), you can ship some tablets. It's that simple. If a company is in financial trouble and they close down the shop in order to prevent people from potentially losing their money when they go bankrupt, then they are making absolutely sure they will go bankrupt, because they're closing their source of income. Also as pichlo mentioned, in most jurisdictions this is not even legal to do and you might even become personally responsible (and bankrupt as well) instead of just the company.

And this is just plain stupid, as Lastu apparently never even received the money. Apart from that, I highly doubt that they'd take them back if there is no market for them (almost no tablets).