Cancel rent offset for a tenant who cleaned building we bought

[Minna Hu]

Hi

We purchased a property last year, a tenant living in one of the apt was cleaning the building for the previous owner, and got $50 off her $650 monthly rent. After we purchased the building, she never cleaned the building, so we cancelled her service and asked her to sign a letter, stating if she didn't move out by end of May last year, she will pay $650 for her rent. But she never paid the extra $50. 

With the signed letter from her, will LTB agree that her rent is $650, and can we evict her due to non-payment of rent? Now we need to give her rent increase notice, can we increase her rent based on $650?

The same tenant, she stored personal items in the basement, before we bought the building. After we purchased the building, we asked tenant to remove their belongings from the basement, she claimed that we threw out her personal stuff, such as Christmas tree, and her kids' photos, and all together worth $1000. She has filed application with LTB, and hearing is arranged in March. 

Our lawyer said we bought the building, so we took the liability from the previous owner, even though there is no proof that we threw her stuff out or even she stored the items she claimed in the basement, neither the value of those items. What is your opinion on this? And what do you suggest to do? Thank you!