You say "22,00" What is this? Is it �22,000 - which seems a tremendous amount.
If you don't pull out you have to represent yourself at Court - very difficult if it is at all complex - & could end up with the decision going against you and a higher award for costs than their present figure. If you win, obviously you would be OK unless they appeal.
If you pull out, or if you lose in Court, you will be liable for their costs. If you don't pay - or come to some arrangement acceptable to them to pay by instalments over a period - they can take enforcement action. This could include making you bankrupt but, if you have no assets and no money then you would not have to pay them anything unless you were deemed to have income surplus to your essential expenditure. If that was the case, & the surplus was �100 per month or more, you would have to make payments for a maximum of 3 years and the rest of the debt would be wiped out. If you have no surplus (or less than �100) you would not have to pay anything.
It would cost them more than �1000 to make you bankrupt so, if they know your circumstances are such that you wouldn't have to pay anything back, they are unlikely to do it. However, the debt could then be hanging over your head for many years to come with the possibility of demands for payment when your finances are much improved. If they don't bankrupt you & you want to make sure the issue doesn't come back to worry you later on you could make yourself bankrupt for �485.