This is not an unusual ploy by your bank; I have heard of such before. The bank's primary concern will be ongoing mortgage payments and, as they are probably loaded up with repossessed properties, they will do all that they can to remove the potential threat of another. The equity in the property is largely an irrelevance; they do not want to take any risks now.
The likely solution, as intimated by Maria, is a Remortgage to another bank to repay both the existing mortgage and loan. If you do intend to sell soon then look for an 'Interest Only' product to keep the obligations to the new lender at an absolute minimum.
However, it seems that your existing arrangement (with a payment of €900 per month) may be set up on a Repayment basis (Capital and Interest); have you not asked the lender if they will consider an 'Interest Only' period for you for a year or so to give you that window of time to ese the pressure and allow the sale? Many if not most banks will offer such now, but only if you ask for it!