Backup in Laundry Tubs

We are experiencing a back up of sewerage in our laundry tubs. I called out a local company and they rodded out the line Friday for $170. I went to do laundry Saturday and experienced the same problem. They said there was a 6 month guarantee on the rodding so I called them back out. They came back out and said the problem must be in the main line. They said they need to remove the toilet and rod out the main line. This would be another charge of $350. The plumber said he could talk to his manager and see if the $170 could be deducted from the $350. I am just very flustrated that the plumbing company didn't know it was the main line in the first place and we really don't have the money to spend to have more done. My husband is very handy and is Mr. Fix it around the house. He was thinking of just renting a power rodder and rodding it out himself. Is that very easy and safe. We do have a cleanout in the front yard. Would it be possible to start from that end and drill through to rod out the clogged pipe? I did have an apple tree in the front yard but it was removed over a year ago so I'm wondering if the roots are still down there somewhere. HELP!!

First of all the plumbing company initially didn't diagnose the problem; therefore they are obligated to open the drain line that they should of done to begin with. No plumber around should be able to get a double charge on a customer for this type of situation. I would bring down the wrath on this company and force them to correct the problem before the local news station finds out......or better yet the Better Business Bureau. It is your money to spend. Drain cleaning is very dangerous if you have no experience using the equipment.