I explained the situation. I just moved in and paid for a month and a half to start,and since they're trying to milk me for more that is not my responsibly after one week, I seriously doubt I'd see one cent of it back.
So you are renting a room from someone who is also a tenant, paid for a month and a half rent, and just moved in to find an infestation of cockroaches and the landlord (who is really the other tenant) keeps hitting you up for money to pay for things. Right?
IF so,what was the pre-move-in agreement regarding expenses? Is there a lease or other writtten agreement? Did you agree to split the utilities? If there was an agreement (written or verbal), then you are obligated to follow the agreement. If there was no agreement, then you are under no obligation to pay any more than the $500/month.
I don't know what you mean about paying to maintain her old road. If she is a tenant (total rent is $800, and you pay $500) she shouldn't be maintaining the road. That should be up to the owner of the property.
Regarding cockroaches. If you work out the financial situation with your roommate/landlord and decide you will stay, then you may want to pay for an exterminator yourself (after coming to an agreement with roommate/landlord about keeping them at bay).
As a landlord, if there are fleas/cockroaches when a tenant moves in then I immediately pay to get rid of them. Recently had a tenant move in and they found a few fleas jumping as they moved in. I immediately flea-bombed the house and took care of it. Haven't had a problem with cockroaches, possibly because I ensure my tenants keep the house adequately clean (yes, I know cockroaches can live in clean houses).
If you cannot come to an agreement about finances and bugs then I would use this as an expensive lesson and start looking at moving. There is a term in business called "sunk costs" that means money that has been sunk into a project that appears to be lost, and it's not worth throwing more money after the problem just to save the original investment. You may be at this point where your first $750 is a sunk cost, and you may just need to let it go and move on. Never live with someone without a written agreement that spells out financial obligations.
Best of luck, pls let us know how it turns out.