Hi Imogene, 

Regarding what you said about "not having done a good enough job": the continued carpenter bee activity has nothing to do with how you removed them. Carpenter bees have an annual life cycle. The bees you're seeing this year are not the same you saw last year. Every year, there will be a new population of bees attempting to colonize wood.

Regarding the bees requiring relocation: carpenter bees are just raising their young in those nests, they don't live there. So I'm confused that this company required you "relocate" the bees. Are you sure that is the phrasing they used? 

I am not familiar with any carpenter bee management that involves relocation. If you were able to keep the nest tunnels intact and move them elsewhere, the mothers would lose track of them and be unable to provision the larvae (leading to starvation, unless they're already fully provisioned at the time of relocation). Most carpenter bee management involves killing the bees, and/or treating the wood to ensure further damage is not inflicted. 

There are companies that remove honeybee swarms/nests, but none that specialize in carpenter bee removal. There are a variety of pest control companies that could kill the bees, but you could implement these same measures yourself (saving lots of money). I cannot recommend specific companies (due to CSU policy), but here is a list from the Better Business Bureau.

https://www.bbb.org/us/co/denver/category/pest-control

The best way to manage carpenter bees is to paint vulnerable wood, as the bees will avoid tunneling into painted wood. More interventive strategies involve applying insecticidal dusts to the nest entrances, or creating traps. Insecticidal dusts are best applied in the early spring when the tunnels are still being excavated. The traps can be bought, or made at home. 

I appreciate that you don't want to hurt the bees. Thankfully, carpenter bees are quite common. There is probably ample habitat for them in the areas around you, so you are likely to continue to enjoy their presence after eliminating the current infestation. After that, installing painted wood is the best way to prevent bee damage without using insecticides. 

Let me know if you have further questions.