If you hear from your customers that they are not happy with the clean, try and find out what exactly they were not happy with. Always ask for their feedback and suggestions on the spot so that they can point out immediately what needs to be corrected :)
A customer who is more willing to give their feedback and suggestions to you on the spot would be more likely to engage you a second time. The key to being the best cleaner on the platform is to always face each feedback with a smile and always seek to improve your skills.
All the best!