Billing

I've been with xfinity mobile since August of 2025 and I've been overcharged every month since. They have 5 phones listed on my account but I have only 4 phones. One phone is listed twice and I'm being charged twice for the same phone. I've chatted 3 times with no success and went into the store once and no one seems to know how yo resolve the issue. Each time customer service agrees and gives a credit for what I'm owed,  but can't stop the charges from reoccurring the next month. It's ridiculous that a company this size can resolve a simple problem like this. Currently I'm owed $79.15 because I didn't reach out each month and some credits didn't equal the charge. I just want the charge removed permanently and a refund of what I'm owed. It shouldn't take a year to solve an issue.