We use a Travel Agent as well. He's worked with us for close to 10-15 years and is really straightfoward with his recommendations, as he also takes his family on cruises across various lines. He knows our needs and likes. Sometimes he sends us Bon Voyage gifts on Embarkation Day.
He also works directly with the cruise lines if there's any issues. For example, I'm trying MSC next year and had an issue with joining the Voyagers Club and getting my Status Match. I had been waiting well over a month to get my membership number, which he then would use to bring my faire down. He told me it could take up to a month to get that number and as soon as I got it, I was to email it to him.
Almost 2 months after not recieving the approval, I emailed him, per his request if I had any issues joining, so he could intervene. I sent him my information that MSC requested, he tried applying on my behalf and got the same error message I had been getting. He then called his contacts at MSC and told them what was happening and mentioned that I had emailed them a few times as well asking for updates. He was able to verify that there were technical issues on MSC's side, which they were actively persuiing to a resolution.
About 2 days later, I got an email from MSC officially accepting me into the Voyagers Club, along with my Status Match and membership number. I emailed my TA that day, thanking him for his assistance and providing him with my membership number, which was then applied to my faire.