As a landlord. I am VERY sure, that we have to make sure the place is as pest controlled as possible for new tenants.
do you rent through an agency? Did you fill in an inspection report when you took over the property? IN the fine print, I am quite sure you will find something to the effect of how long you have (and I'm sure 2 weeks would come within that time frame) to report things like this and have them rectified BY the landlord.
Do bear in mind though, that sometimes, if a place hasn't been sprayed in a long time (depending on how long the previous tenents wer there, they may not have sprayed in many years and might have lived like ferals and the place was infested +++ by the time they left!) that what sometimes happen, is after a good spray, the bugs come out and go nuts for a few weeks. BUT - you can usually tell if this is the case because they are dying all over the place NOT healthy and alive
Probably, the previous tenants didn't get it sprayed at all and this wasn't checked
Anyway, If your landlords or agency refuse to do something asap, then I think you should ring your Rental Tenancies Authority in your state.
That's just not acceptable. I would never expect my tenants to have to put up with that.