Why is my Optimum Boost NEVER reaching 30mbps?

Regular Optimum is supposed to be about 15mbps, we ordered optimum last saturday and were getting about 7/12mbps average. so we decided for $10 why not just get boost? so we did. instantly the speed went up to 30mbps for the whole day…it was incredible!! then for the next 5 days, it wouldnt go above 14mbps. so we called optimum and they scheduled an oppointment, the DAY he was supposed to come, we got 30mpbs all day again…JUST that day. So he left and said everythings fine. that was yesterday…now im back to 11mbps!!! its almost like they knew he was coming so they “fixed” it, and then when he left they sucked it right back from us! anyone else having this problem???