This will vary greatly from area to area but in most places for a tenant to withhold payment legally the property generally has to have a problem that would make the property “unliveable”. Like the front door falling off the hinges, no water or no functioning toilets or the landlord has to ignore the problem for an unreasonable length of time.
The A.C breaking in the beginning of summer and it taking a week to get an A.C company to look at it probably doesnt count. Them leaving the A.C broken for the whole three months probably does.