Rent in the form of cash what I need to know

[Allen McGlashing]

Hey guys so I just inherited a tenant from the property I had just purchased so he's on a fixed lease ending in December. Now I just had an hr conversation with him cause his rent wasn't in the mail so on his lease it says he is paying $325 a week instead of $1,300 a month which is ok I guess (if he pays), but he wants to give me cash each week I just want to know what I should do as in like give him a paper receipt just documenting. Also what would happen if he misses a week payment mid month can I send a 14-day notice or would it be void because I technically excepted partially payment?