The best way to handle these types of information lines on your credit report is to dispute them but you have to remember that if that isn't done correctly, it is like kicking a hornets nest. Just calling them and saying, "hey, I dispute this." is NOT good enough, regardless of what ANYONE says. It has to be done with a certified, return receipt letter that has been properly worded to prevent the sleezy little buggers from using a loophole. You can find a lot of information out there about how to do this on sites from people like Dave Ramsey or with self help books like Weathering Debt (either one works, but I prefer Weathering Debt, it was much more concise and to the point) but whatever you do, DON'T try to wing it and don't pay someone to do something you can do yourself with ease and for free. Besides, you need to know how to stop the problem from happening again, right?
Many companies that claim to be able to fix your credit simply have a poor track record of delivering on their promises. Several turn out to be credit monitoring services in disguise that do nothing more than provide you with a credit score and fancy tools to monitor your credit. But what you're actually paying for is the cost they incur to obtain your score and subsequent reports. Some companies can also temporarily remove items from your credit report, but these items will eventually reappear and you're back at square one. When they cannot repair your credit by traditional and legal means, some credit repair companies turn to outright fraud including creating a new identity with a new social security number. These tactics are illegal and can end up costing you more in the long run.
Making your credit payments on time is one of the biggest contributing factors to your credit scores. Some banks offer payment reminders through their online banking portals that can send you an email or text message reminding you when a payment is due. You could also consider enrolling in automatic payments through your credit card and loan providers to have payments automatically debited from your bank account, but this only makes the minimum payment on your credit cards and does not help instill a sense of money management.