Example an formal letter

Dear Ms o Mr,/Dear Sir/Madam

I am writing to complain about the last changes that come from your company such as, the course fee has recently increased by 15% and the meetings will be moved on tuesdays and fridays./I am writing to complain about the last changes by your company, most especially the fee increase of 15% and the meetings moving to Tuesdays and Fridays.

According to them, I would like to express my dissapointment, because I joined in this course believing that the prices will be kept./Because of them, I would like to express my dissapointment. I joined in this course believing that the prices would not change.

At the moment, my salary is low and I cannot afford to pay more money for this service. In the other hand, if you change the meeting days, I would not come here because I usually work on these days./At this time, I cannot afford to pay more money for this service. Also, since you changed the meeting days, I cannot attend because I work on those days.

Then, I would suggest alternatives, as: First, keeping the prices to people that actually do not afford to pay or you could give discounts to unemployed./I would suggest alternatives such as keeping the prices the same because people budgeted that amount or possibly give discounts to the unemployed.

Second, all the members could meet other days in social networks./As for the meeting days, I suggest using social networks for those unable to meet on Tuesdays and Fridays. 

Thank you for help/Thank you for your consideration. I look forward to hearing from you.