So? Your expectation of the business practices of one store based on how some others run theirs is your error, not HMV’s. The T&Cs of both operations made it fullsomely clear they operate as seperate businesses with different pricing structures and no crossover between them. Your desire to conflate the two into one homogenous whole is not their problem.
Maybe not, but it is still a poor concept on their part. Using the same logo and a very similar name is always sneaky.