From past experience, if you miss the payment your policy will still run for about a month n half before they ACTUALLY suspend the policy, so miss the payment, when they send you a demand next month pay it and all will be fine, tell them your DirectDebit got cancelled and that your working on getting it resolved but your away on work and nowhere near the car or your documents for the next few weeks, Tell them anything really to stall them!
On another note, Your company isnt LEGALY allowed to keep your wages away from you! Demand your wages for the month in full and they are required by LAW to give it! Unless of course you've done something to loose them money then your pretty much screwed.