Hey tanmizi! I'm so sorry you haven't had luck contacting us so far - I hate that you've already put effort into this without getting it resolved. I assure you there is an escalation process for this exact situation - this misunderstanding based on the packaging can happen, so once in the lifetime of any account we're able to accept the refill cards and void the balances, then apply an adjustment to your postpaid balance in the same amount.
Unfortunately, since the Support Community is a user forum, we can't complete this process for you ourselves. I'm confident that if you reach out to our stellar T-Force team via FB or Twitter regarding this matter we can make it right for you. Once you've messaged them and verified your account, you can link to this thread so they can see the process I'm mentioning! Please let us know how this works out for you.