pair of sandals, one size 5 an dteh other size 6

i purchased a pair of red gladiater sandals from Mr Price last month. i wore i two time now and only to realise my feet had gotten saore on teh left side. so i examinde my sandals as to find out why. i found that teh pairs were a size 5 left foot and size 6 right foot. i spok eto teh mnager there yesterday an dseh had told me she cant do anything about it as they dont ahve teh other pair and all of their shoes match. i am so dissapointed. as i paid about 120.00 for thsoe and now cannot use them.