While what you describe is unfair, it is also common and legal. A "pre-approval" is nothing more than a statement that based on what you have provided, you *should* or likely would qualify for a loan--but it is not a loan committment. Until there is a firm committment (e.g. the loan has gone through underwriting), the bank is not locked into providing it, and is not liable if they fail to provide it.While there is technically a legal theory you could try based on the POC telling you to go ahead into escrow (which she should not have done; most will not say this), called "promissory estoppel," which can in some circumstances enforce a promise even without a final contract (or, as here, a loan committment), you would be unlikely to prevail on it: among other things, it requires that your reliance on the promises be "reasonable" and if there was no actual loan committment issued it, a court could easily find that it was *not* reasonable to rely on this statement--especially if there was anything in any of the lender's marketing materials, the application forms, or on the bank's website stating that there is no obligation to provide a loan until after underwriting and a final committment is issued (since if there was such language or statement anywhere, that make any reliance on a statement to the contrary completely unreasonable). Plus a legal action based on this would typically take months, which is likely far too long a time frame for this. You may need to do what it takes to satisfy the lender (e.g. co-signor).I definitely sympatheize: my wife and I recently bought a house and the lender initially told us we could do so at a 15% cash/85% mortgage level; but after getting deep into the process, they suddenly decided that because I am a self-employed solo practioner, they needed 20% cash from us, forcing us to scramble to find another 5% deposit while also footing all the expenses of sale and moving expenses. Lenders do this frequently.