New user - buying stock more than deposited amount?

Hi all, I have just started out learning and have put a light amount of money onto my account to put my research into play, however earlier as I was viewing the FB drop, and I hit the buy button with the price at 273 (by accident on app), however I have only deposit £50 into my account, to my surprise it said I had obtained the stock at 273. I was under the assumption that I can only buy worth of what I deposit - have I missed something?

Many thanks

When you look at your FB holding, which type of account are you in (icon top-left) - CFD, ISA or INV?

How many shares does your holding say you own - I’m assuming you may have purchased £50 of FB fractionals - equivalent to around 0.25 shares.

Are you sure the confirmation is not just that you paid a price of 273 and got a fractional share?