if you dont feel that the mediation would be a success than you should not have applied for Quashing as referring to mediation is of no use than...I feel there is no harm in trying once do send someone on the day appointed may be the other side is also fed up with the long litigation and may be looking for a common ground to talk and finish it at some condition.
Sometimes the most difficult things get sorted so why presume failure in advance. If no one visits than all money in filing the writ would be a waste as the stay will vacate in a month at least take a date of one month that will keep the lower court proceedings still stayed.
And if it gets solved your all problems would be wiped off try making someone visit once on the apointed date and if knowone arrives ask for a date. I have seen many are able to arrive at a settlement at the mediation centre and may be god brings a end to your problems.