Albert recently bought an estate home on a one-acre lot. Since he did not have the proper equipment to cut their lawn he arranged for a neighbor to cut the lawn. The first time cutting was difficult as the lawn was very overgrown. The neighbor charged $150 on this occasion. One week later, the neighbor cut the lawn again and charged Albert $100. Mark realized this was getting expensive so he bought his own lawnmower and thanked the neighbour for his services and informed him that if he were stuck in the future, he would call the neighbour to help him out. Shortly thereafter, Albert had to leave on a lengthy business trip and on arriving home discovered that the neighbour had mowed his lawn in their absence. There was an invoice stuck to his door stating $100 for mowing services and $50 for weed spraying. When questioned about the bill neighbour explained that he understood Albert wanted him to mow the lawn if he were unable to. What legal issues does this situation raise and what arguments would be used by the parties involved (consider if one or both bills have to be paid and why)?

Long answer please, with specific details.