Yeah, as others have stated, 30 psi for 7 days is your first problem. That's too high for too long. 30 psi can be used to burst carb and have beer that is ~75% carbonated in about 2 days; however, I would never exceed 48 hours at 30 psi or you risk overcarbonation and when that happens, you get pours like you described. The key to a properly functioning keg system is to make sure the system is balanced for the carb level you typically use. For most of us, we use 10-12' of 3/16" ID beer line, a temp of around 36-40°F, and about 12 psi for carbing and serving. That will get you good carbonation and nice pours without having to fiddle with the pressure once the beer reaches the ~2.3 vols of carbonation that is typical for most ales.
To fix your foaming issue, you need to reduce the carbonation level of the beer. The way you do this is by turning off the gas and periodically pulling the pressure relief valve on the keg several times over the course of a few days until you get good pours. Your keg is like a big bottle of soda and every time you purge the CO2 it is like removing the cap from the soda bottle. Every time you do it, the beer will lose some carbonation.