This is prob a mistake.
If you give them access to your Google account ( for adwords ) and they log into it to make changes and then later while the person is surfing the internet and want to check their email, they go to gmail and are now in your email account by mistake.
Has happened to me lots of times where people give me THEIR main adwords login and not a 2nd login or under my MCC account. Hours later I go to check my gmail and realize I am still logged in as them.
If someone at BoostCTR really wanted to know your shit, they would have came back multiple times after the 5th.