[Estancia]

So far my PvZ is my worst match up.
I rarely lose against aggressive zerg, because I can just go 3gate robo and take advantage of his larvae count and shitty economy and pressure him to death.
The problem is those fast expanding. Back in silver (1 month ago) I've 4gated them everytime, and it usually works because they don't get enough defensive structures/units.
But now that they are decent enough in gold, they'll just mass lings or spines. I can't just damage him, or even apply pressure with those 4 spines and plenty of lings.
The second problem is the mutaling. I've tried pheonix zealot, but zealots get obilerated without any support (pheonix are engaged in vs muta) and having 20 pheonix against 40 lings isn't a good situation.
When I try archons zealot, the mutas makes use of archon's shitty speed and harrass me to death. Any cannon I put down gets taken out easily.
Any tips?